"The Most Interesting Man in the World" campaign was created by "a couple of idiots" who thought up the idea at the last minute before heading into a meeting. The now-famous tagline, "Stay thirsty, my friends," only came to be after the brand team decided against "You have only one life, make it Dos." In the early days, there was a ton of pressure to kill off the entire idea. And during the first ad shoot, a creative director was nearly mauled by a bear.

These are among the secrets spilled to Ad Age by the agency and brand team members who were there from the very beginning of a campaign that is now widely viewed as one of the best ad efforts of the 21st century.

We reached out to some of the original creators and caretakers of the Most Interesting Man as Dos Equis prepares to make major changes to the 10-year-old campaign, including swapping out leading man Jonathan Goldsmith for a new actor, as Ad Age reported earlier this week.

Here are their stories in their own words:

Karl Lieberman

Then: Euro RSCG, copywriter/art director, 2001-2007

Now: Wieden & Kennedy New York, executive creative director

I owe my entire livelihood to that campaign. That's both a good thing and terrifying. It's a good thing because I learned a lot from how we collectively brought that idea to life and have tried to carry that on over the years. It's terrifying because my partner Brandon Henderson and I reluctantly came up with that idea about a half hour before the meeting with our Executive Creative Director Jeff Kling. In a parallel universe out there, the PATH Train would have been running late or an elevator would have broken down that morning and now we'd likely both be penniless and living in our parents' basements listening to Rush albums and yelling at the TV.

I think Brandon and I were 25 or so at the time, a few years into working in advertising and pretty much had no idea what we were doing. We were just a couple of idiots trying to make each other laugh and cobble something together for a meeting on an account we figured we'd never sell something on anyway. In hindsight, that naiveté and recklessness is what made it so good.

I remember after we presented that idea for the first time, one of the CDs pulled us aside, told us how disappointed he was and said that we needed to up our game. He said he was worried we were turning into "Team So-So."

The original notion of that whole thing -- before it went kind of all Chuck Norris on everyone -- was that this guy was sort of only minimally "more interesting" than the rest of us young, neutered millennial guys were. Brandon and I thought that the same way we'd purport this beer to be more interesting because it was an import, we could purport this man to be more interesting simply because he didn't do all the incredibly lame things that we did like alphabetize our DVD collections or use exfoliating facial moisturizers.

Brandon Henderson

Then: Euro RSCG, copywriter/art director, 2001-2007

Now: Wieden & Kennedy New York, creative director

When I'm hit by a bus one day, people will mostly remember that along with Karl Lieberman, I created the Most Interesting Man in the World campaign. What I think about most now, at the moment of his replacement, is how many hundreds of people Karl and I auditioned for this role, and how we ended up casting the second guy we saw.

Jonathan Goldsmith was right from the start. It felt like he wasn't acting. He could freestyle for 10 full minutes about a dignitary dinner he attended with the Queen, and how he lost a tooth there biting her crown to prove it wasn't real gold.

At casting callbacks, he had an old dog that followed him around that he called The $100,000 Dollar Dog, but he never said why that was. And when our original script called for a scene where he dove off a burning boat into the ocean with a knife between his teeth, he seemed up for that too. He had been on Manimal. And CHiPS. Like I said, he was right from the start.

The second closest guy kind of looked like a henchman in a James Bond movie. He had one of those mid-90s Caesar haircuts with bangs you could cut glass with. I remember he wore a lot of turtlenecks.

Jeff Kling

Then: Euro RSCG, executive creative director, 2004-2008

Now: Fallon, Minneapolis, chief creative officer

At this point, I'm deeply concerned that our hard-working campaign creators won't get due credit for all the amazing sub-campaigns we spawned. For example, I want desperately to be remembered for this contribution to world letters on behalf of a place called Albert G's in Tulsa, OK, spotted just yesterday at the Tulsa airport:

Were it not for the tireless contribution of so many and for the visionary shepherding of this work through several approval layers at Heineken and then Cuahtemoc Moctezuma Brewery, this Tulsa BBQ joint and so many others would be fucked for an idea.

[The campaign's] Director Steve Miller has a buddy who does a fairly complete volunteer job of tracking The Most Interesting Man's communications offspring.

In truth we had given up all hope of doing anything interesting for Dos Equis, when a miracle substitution on the client side put a Dutchman named Willem Vanderhoeven in charge. Spectators will find it hard to credit reports that this particular campaign was nearly impossible to navigate and wheedle into existence, but it was dead on the table in two breweries without Willem and Arturo Rojas. Facts.

Ken Kunze

Then: Heineken USA, chief marketing officer, 2006-2008

Now: Craft Brew Alliance, chief marketing officer

We had a consumer segmentation study and the target segment was "monsters" -- young guys who go out A LOT, and drink A LOT and don't care what they drink. This was the insight that informed "I don't always drink beer" line. The line was controversial internally, but it was rooted in consumer truth.

Casting an old guy was controversial. Originally Euro presented younger guys more in the target. But the concept wasn't credible without the guy being more seasoned. The inspiration was the uncle who never got married and was always doing cool shit, Hemingway-esque. He doesn't really speak in the spots so he was chosen for his look. We spent more time talking about his beard, whether it was OK to have one and how grey it should or shouldn't be.

Because FEMSA still owned the brands at that time, I had to get them to buy into strategic moves. This new campaign needed their buy-in before we could produce it. I remember having over a three-hour conversation well into the night with my counterpart in Monterrey, Mexico, discussing the concept, the scripts, etc., trying to explain the nuance of the idea to a guy who was pretty literal and whose first language was Spanish. And at the end of three hours he simply said, "I don't get it. But we know you are passionate about it and we trust you."

So the next day I called Kling and told him the story that they didn't get it and didn't really like the campaign, but they committed to support its development because they trusted me. So I asked him if he was sure it was going to be as good as we thought it was. And he gave this "yeah, sure" kind of answer. But I said to Jeff that I really needed to know that he was personally committed to make this great because I felt like I had really put my balls on the line for this campaign, and I really wanted to make sure he was committed and had his balls to be on the table with mine….yeah sure. So then I went to Andy, the HUSA president and told him the story and he basically said your balls are on the table, but so are mine.

The original tagline was a lame translation of the strategy statement, something like "Dos Equis, the most interesting beer in the world." Our challenge was always can't we say it without saying it. And right before the work was going to be shown at the [distributors] convention, Kling called me up and said I think I've got it, would you consider changing the end line to "Stay thirsty, my friends."

The work initially debuted at our wholesaler convention to about 5,000 people. We had just finished a dress rehearsal the night before at about 9 p.m. and the VP of sales comes over and goes, "We can't show it, the works no good." The marketing team and the agency knew it was good and the next day the response from the 5000 wholesalers was instantaneous. All the doubters became believers.

FEMSA came to Heineken USA because of the work we had done on brand Heineken. They wanted Dos Equis to be more like Heineken at the time. By the time the campaign launched, the Dutch in Amsterdam were like, "How come we can't get work like the 'Most Interesting Man' on Heineken?"

Caroline Krediet

Then: Euro RSCG, Planning Director/Group Planning Director, 2006-2009

Now: Figliulo & Partners, partner and head of strategy

When we originally tested this campaign there was great debate about how old the MIM [Most Interesting Man] should be, with the agency favoring the old guy. So we went into research with multiple photos of the MIM as a 20-something, 40-something, 60-something. The unanimous feedback was for the old guy who they felt would have the most and best stories. The younger guy would be a "total douchebag" who they wouldn't take advice from. And so we were able to write a MIM casting spec for a distinguished old dude. Enter Jonathan Goldsmith.

Jonathan Goldsmith was in one of those ads for old person's home rescue alert buttons. "Help, I've fallen and I can't get up," which ran right at or just before the first airings of the MIM launch campaign.

When we were deciding on the tagline, then-brand team [members] Willem van der Hoeven and Lisa Pfenning made the big bold decision to walk away from the safer, more "marketing" tagline, "You have only one life, make it dos." They picked the epic "Stay thirsty, my friends."

Then-CMO Ken Kunze wanted to have the MIM holding a glass of scotch in one of the scenes (to show he doesn't always drink Dos Equis) but efforts were foiled by advertising standards.

Mary Perhach

Then: Euro RCSG, group account director/global chief communications officer, 2005-2011

Now: SwellShark, president

Some of the best times in my career are linked to this campaign. This was an incredible team -- agency and client. If you swapped out any of the players, I'm not sure this campaign would ever have come to life.

When we pitched the campaign, we imagined the MIM as an older man -- the embodiment of a life well-lived. In fact, we used Prince Rainier in the comps. We wanted to address any concerns about casting a gray-haired man so we created additional comps for focus groups with a few younger men in them. One of the faces was David Turkanis, who was the AE on the business at the time. Not sure he ever officially agreed to that but we all got a kick out of it. Side note: The closer the MIM was to the age of our respondents, the less appealing he was. He became threatening and they disliked him. The MIM was meant to be aspirational and that only worked when he was significantly older than the target, since that gave the target a few decades to become just as interesting.

Karl, Brandon and Jeff are some of the best writers in the business. Their lines were so clever and so well-crafted. I know the campaign would have been a bust if not for the amazing writing.

Karl and Brandon wrote some rules for the campaign for the writers that would come after them. One of the biggest was that what we claimed about the MIM's exploits had to be possible, if not probable. That's why they always qualified some of the more improbable claims with language like "It has been said that...."

On the day of the campaign launch, Willem gathered the entire team in a conference room in White Plains [N.Y.] and gave a speech about teamwork that would rival anything Gene Hackman said in "Hoosiers." Still gives me goosebumps.

Lisa Pfenning

Then: Dos Equis brand director, 2005-2008.

Now: William Grant & Sons Inc. category marketing director, Sailor Jerry & Tullamore Dew

One thing that many people don't know is how hard it was to sell this campaign into the Heineken senior management team and the Dos Equis brand owners (at the time the brand was owned by FEMSA). Aside from our direct team and my CMO at the time, there was not much enthusiasm for the campaign. In fact, a few people wanted to kill it. It was one of my toughest stakeholder management endeavours. The business finally agreed to let us shoot the campaign but we could not air it until we had LINK [copy testing] results back. As you can guess, the campaign blew the category norms out of the water, which allowed us to launch.

When our CMO was going to bat for this campaign he called Jeff Kling and said "I'm putting my balls on the line for this campaign and I want to know that your balls are on the table right next to mine."

During year one of the campaign, we actually wrote a plan about how to "evolve" (aka kill off) the MIM should the campaign lose its relevance.

The grizzly bear we used in the launch spot broke free during the shoot and almost mauled one of the creative directors. That was the day I swore I would never work with live animals in a shoot again.

Editor's note: Below is actual footage of that brush with death, now posted on YouTube and verified by one of the original team members.

Christian McMahan

Then: Heineken USA, chief marketing officer, 2008-2010

Now: Managing Partner, Smartfish

When I arrived on the scene and the campaign was still in test markets, there was still resistance on taking the campaign national. CCM was still the brand owner in those days and they were very protective of the brand and the trademark. We actually had to convince [them] that the campaign would work at the national level and would succeed. In 2009, the campaign went across the U.S. for the first time and has stayed that way ever since.

Before we broke the campaign national in 2009, we established the "MIM Commandments" -- a series of rules designed to keep the campaign fresh and not wearing it out too soon. As still a small brand at the time, we could not afford having to create something new, we wanted to make sure the campaign had a long run. I can't reveal all of them, but I think the biggest takeaway was to avoid the "jump the shark" moment. No late-night talk shows, no movie cameos, etc. Not too much later Old Spice launched their "Man Your Man Could Smell Like" campaign and broke almost all of the rules. The campaign was great, but certainly seemed to wear out a lot faster than "MIM" did.

One of the more amusing things was the annual approval process. One year we had a line in one of the spots that was one of my all-time favorites that said "Sharks have a week dedicated to him". A no-brainer, right? Well when you fly down to Monterrey, Mexico, to present the spots and the senior CCM executives all look at each other after the ad plays, you then have to spend a few minutes explaining the cultural phenomenon of Shark Week. Another awkward moment was after Heineken purchased the brand, we flew to Amsterdam in 2010 to present the new work. We had a spot that year called "Manscaping," suffice to say it was not my proudest moment as a marketer to have to explain what manscaping was to the Heineken leadership.

Paul Smailes

Then: Dos Equis, senior brand director, 2009-2012.

Now: SwellShark, managing director

One of the secrets to the brand's success was a magnificent client-and-agency partnership. Our agencies were a valued extension of the marketing team who had an equal (and at times a deciding) vote on important decisions and who acted as one team when evaluating and executing ideas in the best possible way regardless of their origin.

One of my favorite memories was holding a pirate-themed offsite which pushed the team not to rest on our laurels, motivated us to think like a challenger brand, reminded the team of the brand's '10 commandments', and to inspire a new wave of fresh ideas. Seeing some pretty serious debates by men and women dressed as pirates was also very amusing.

Jonathan Goldsmith was a pleasure and gentlemen to work with, and was very gracious in understanding why he couldn't accept every event invitation he received each week so we could keep the mystery of his character alive and well.