It's one of country music's most unexpected friendships, and one that produced an epic 2015 CMA Awards performance that still gets talked about to this day. But Chris Stapleton and Justin Timberlake first got to know each other not by talking about their shared musical careers, but rather by talking about their kids.

Back in 2015, Stapleton was a buzzy singer-songwriter with a history as a member of bluegrass group the Steeldrivers. His solo debut, Traveller, had come out earlier that year, and he was nominated for three CMA Awards: New Artist, Male Vocalist and Album of the Year.

By the end of CMAs night, not only had Stapleton picked up all three of those trophies, but he'd also given an unforgettable, eight-minute-long duet performance of his own "Tennessee Whiskey" and Timberlake's "Drink You Away." It seemed like a surprising pairing at the time, but Stapleton says he and the pop star from Memphis were already friends, so he simply asked Timberlake to join him on the awards show stage.

"I've known him for a few years," Stapleton told Taste of Country before the 2015 CMAs. "When I thought we were gonna have some nominations and maybe a slot to play, I called him up and asked him if he'd be interested in playing the show."

According to Entertainment Weekly, the two singers had been waiting for the right opportunity to team up ever since a mutual friend introduced them a few years prior. Before they ever got the chance to work together on a musical collaboration, they kept in touch over "dad stuff," Stapleton explains.

"We tell a lot of kid stories. He's a new dad and I've got little kids," the singer continues. Stapleton is a father of five, while Timberlake is a dad to two sons. At the time of the 2015 CMAs, Timberlake's oldest child, the now-six-year-old Silas, was an infant.

Whatever it was that brought Stapleton and Timberlake together, it worked. The pair brought out the best in each other when they took the stage at the CMAs, Timberlake boosting the newer performer with his practiced onstage showmanship and megawatt superstardom, and Stapleton treating a major awards show stage to his punch-packingly soulful voice for the very first time. It wasn't the last time the two would team up: Three years later, they reunited on the stage of the 2018 Brit Awards.

Now a bonafide superstar, Stapleton hasn't lost his taste for surprising onstage team-ups. At the 2021 CMA Awards, he joined first-time CMAs performer Jennifer Hudson for a stratospheric and raucous rendition of "You Are My Sunshine," a standout moment from the night.

Backstage that night, the singer shrugged when asked what his secret is for creating iconic on stage moments, saying he doesn't typically realize in the moment that he's making musical history.

"No is the answer to that — I don't realize it," he said, "But I do realize that I'm having a really fun time, and that's what music is for me."

Ultimately, for Stapleton, the most important way to ensure the crowd has a good time is to make sure he's having one, too.

"I always feel like if we're having fun playing music, someone's going to have fun listening to it or watching it. If you're thinking about something other than having fun and playing music for people who wanna hear it and also wanna have fun, then you've missed the mark," he reasoned.

2021 CMA Awards — Best Pictures From the Show

The 2021 CMA Awards brought surprise collaborations and electric performances from artists like Luke Bryan, Eric Church, Jason Aldean, Carrie Underwood and Miranda Lambert. Newcomers Carly Pearce and Gabby Barrett also took the stage. This gallery of pictures from the show includes candid show moments as well as pictures taken during emotional acceptance speeches. The 2021 CMA Awards were broadcast live on ABC from Nashville's Bridgestone Arena on Nov. 10.

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Taylor SwiftCarrie Underwood and Luke Bryan all make this list of the 50 best CMA Awards moments, but so do legendary acts like Johnny CashLoretta Lynn, Barbara Mandrell and Dolly Parton (multiple times!).