NFL player Peyton Manning announced his retirement in March after a storied 18-year-run. And while he'll go down in history for his brilliant athletic career, his colleagues, family and friends will also remember him for his famous heartfelt, hand-written letters -- thank you notes or words of congratulations that he penned to those he respected and admired.

To return the favor, Gatorade, along with some of the recipients of his famous notes, have come together in this beautiful tribute ad honoring No. 18 on the day of the NFL draft. In it, those who touched his life read back the lines Manning had written to them, turning his words into a new message of thanks and well-wishes for him.

The Pepsico brand and TBWA/Chiat/Day Los Angeles worked with members of the Manning family to gather together all those who appear in the ad.

Among them are Manning's former coaches, including Tony Dungy, his Indianapolis Colts head coach from 2002 to 2008 and David Cutcliffe, Duke head coach and Manning's coach at the University of Tennessee; his former teammates Jeff Saturday and Brandon Stokley; his family -- brother and New York Giants quarterback Eli Manning, and father Archie, an NFL Hall of Fame quarterback and his friend and fellow Gatorade athlete, the New York Yankees' Derek Jeter, who also received his own moving farewell from the brand, the award-winning "Made in New York" spot.

The tribute film is set to Bob Dylan's 1964 classic tune "The Times They Are A Changin." It was directed by Smuggler's Henry-Alex Rubin and will air tonight ahead of the NFL Draft.

The production proved challenging, especially with the agency "having to keep this big secret from Peyton, as well as hunting down new letters along the way," said TBWA/Chiat/Day Senior Copywriter Kathleen Swanson. The agency filmed in eight cities over 18 days, "a fitting production schedule for #18," she added.

As for the decision to not include Mr. Manning in the ad, "Gatorade wanted a tribute just as powerful as "Made in New York", but didn't want something that felt like a sequel," said Global Creative Director Renato Fernandez. "Our goal was to create something unique to Peyton and his genuine character. He's a humble kind of guy, known for writing these wonderful heartfelt letters throughout his career. It just didn't feel right for Peyton to be in his own goodbye film -- so instead, we made a film for Peyton."

Mr. Manning was unaware of the ad until recently.

"He didn't know about the idea until this week," said Gatorade Director Campaign Integration Lauren Fritts. "And when he did see it, he was completely moved. We couldn't be happier with the result and hope it resonates just as well with Peyton's fans."

Also as part of the campaign, Gatorade and the agency have created a mural dedicated to Manning, which appears at the NFL draft village in Chicago through Sunday. Since Mr. Manning isn't big on social media, it features real Tweets about the player.