When Snickers was considering its Super Bowl ad options in 2010, Betty White almost didn't make it. The brand's agency, BBDO, had actually recommended going with Aretha Franklin.

"She was the bigger star," recalled David Lubars, BBDO's chairman and chief creative officer for North America, at the Association of National Advertiser's annual conference in Phoenix. Ms. White, of course, made the final cut at the urging of brand-owner Mars, launching a comeback for the comedic star, as well as the Snickers bar.

During a dual presentation at the ANA, Mr. Lubars and Mars Chocolate North America President Debra Sandler gave a behind-the-scenes look at how the wildly successful campaign came together. The seeds were planted many months before the Super Bowl ad, when Mars decided to launch a global campaign for the brand, which had been relying on a regional approach.

"Peanut power was always at the heart of the brand," Ms. Sandler explained. But Mars wanted to give Snickers a more emotional appeal by taking a "storytelling" approach. The result was the "You are not you when you are hungry" campaign, which portrayed Snickers as "the bar of substance that sorts you out," she said.

The Betty White spot, in which she appears as a football player who is "playing like Betty White," went viral, generating tons of free media for the candy bar, while marking a comeback for Ms. White, who went on to appear on such shows as "Saturday Night Live."

The buzz created just the kind of momentum Mars was looking for as it spread the campaign globally and regional brand teams called for similar ads. The campaign is now running in more than 80 countries.

But as Ms. Sandler and Mr. Lubars explained, the Snickers team allowed local markets to adjust the ads, using their own celebrities. "When each region gets to do their own executions ... then they feel an ownership of it," both at the agency and brand level, Mr. Lubars said.

Back in the states, the Aretha Franklin ad -- which was shot at the same time as the spot starring Ms. White -- eventually ran. (It also starred Liza Minnelli.) Snickers has since tapped a range of celebrities for the spots, including Robin Williams. And the candy bar, meanwhile, is on the verge of becoming a $1 billion brand in the U.S., Ms. Sandler said.