On Saturday, at the 2014 Buffett-fest, the billionaire boss showed off his bona fide musical chops, singing My Way with Paul Anka.  The two men performed their duet in a video that was shown to shareholders at the start of the meeting at Omaha’s CenturyLink Convention Center. What happens inside CenturyLink Center each May generally stays inside CenturyLink Center (no broadcasting allowed), but Buffett and Anka, who wrote the signature song for Frank Sinatra in 1968, gave Fortune exclusive permission to publish the video of the new duet:

Buffett and Anka met three years ago at a charity event in Anka’s native Canada, but it wasn’t until last summer when they saw one another again at a NetJets party in Las Vegas (Anka, a NetJets customer, performed; Buffett’s Berkshire owns NetJets) that they considered collaborating. “Warren said, ‘We’ve got to do something together,'” Anka recalls. “We just kept kibbitzing, and that led to ‘Let’s do a video.'”

Buffett gave Anka clear instructions for rewriting My Way his way. He wanted the new version to recognize Berkshire shareholders (“our owners”), his longtime partner and vice chairman Charlie Munger, and Debbie Bosanek, his assistant since 1993, whom he calls the “true brains, guts and glue” of Berkshire Hathaway. Though the anthem he wrote for Sinatra was narcissistic, Anka says he and Buffett agreed that this version “would not be ‘me me me’ boastful.”

In late March, Buffett flew to Los Angeles and met Anka at Hollywood’s Capitol Records Tower on a Sunday afternoon. Anka urged him to “talk-sing,” and Buffett nailed the song in one take. “He was just amazing. He’s so real and on top of it,” says Anka, whose string of hits, starting  in the 50s, include Put Your Head on my Shoulder, Puppy Love and Tom Jones’ She’s a Lady, as well as the theme song for NBC’s Tonight Show.

At 73, Anka is back in the game not only for singing with the king of capitalism. Love Never Felt So Good, a song that he wrote and produced with King of Pop Michael Jackson in 1983, debuted last Thursday on the iHeartRadio Music Awards and is on Xscape, a posthumous Michael Jackson album of never-before-heard tracks that’s due out May 13.

“In May, I’m working with the two biggest rock stars of all time–Warren Buffett and Michael Jackson,” quips Anka.

On Saturday night in Omaha, at a party at Pitch Pizzeria, I asked Anka how he came to write My Way. He was a 20-year-old kid performing at the Sands Hotel in Las Vegas in 1961 when he started hanging with the Rat Pack–Sinatra, Dean Martin and Sammy Davis, Jr. One night in 1968, Sinatra invited Anka to dinner at the Fountainbleu Hotel, told him he was quitting show business and asked him to write a song for his final album. “I went home and wrote from 1 am until 5 pm,” recalls Anka, who had found the music for My Way during a visit to France and acquired the song as well as the rights to rewrite the lyrics. Anka gave Sinatra a demo record, “and two months later he called me and said, ‘Kid, listen to this.’ He put the it up to the speaker. I started crying.”

My Way went on to be sung by other stars, from Aretha Franklin to the Sex Pistols to, now, Warren Buffett. “We’re doing it again–something very special,” says Anka, hinting that another Buffett musical collaboration may be part of next year’s Berkshire shareholders meeting. He will say no more than that. All we know is that nothing seems to stop the 83-year-old Buffett from testing the limits of alternate career.