When Rascal Flatts and the Backstreet Boys hit the stage at the ACM Awards on Thursday night, look for their medley to contain a few surprises. “We close out with ‘Thriller,’” bassist/singer Jay DeMarcus jokes to Billboard.

Maybe not, but they will sing a combo of BSB and Rascal Flatts hits with the two groups relying on their trademark harmonies. Rascal Flatts guitarist/vocalist Joe Don Rooney had nothing but praise for their new duet partners following rehearsal.

“They’re just such great singers and their melodies are so good,” he tells Billboard. “They know how to stack them. It’s like a wall of vocals. It’s really, really cool and really an amazing, powerful sound.”

The medley will include “What Hurts the Most,” Rascal Flatts’ 2006 Hot Country Songs No. 1 that the Backstreet Boys perform with the trio on Life Is a Highway: Refueled Duets, a June 6 collection of remakes of Rascal Flatts’ most-loved hits that pairs the trio with such artists as Jason Aldean, Blake Shelton and Kelly Clarkson, as well as Jonas Brothers on their new single “I Dare You.”

Rascal Flatts came back following a five-year hiatus for their 25th-anniversary tour, which kicked off a few months ago and lasts through the summer. Following the break, they admit it took them a little while to get their sea legs back. “It took me a couple of weekends,” DeMarcus says. “Definitely the first weekend I got out there, I was winded, and I was like, ‘I gotta get my show legs back.’ My back hurt.”

“He’s like, ‘Are you guys sore at all?’” lead singer Gary LeVox adds.

As the trio revisits their hits in concert, some have taken on new meaning as the years have passed.  “When we cut ‘My Wish,’ I didn’t have kids, so now that my kids are 13 and 15, it means a whole different thing to me now when I sing that song,” DeMarcus says. “I think that for all of us, different seasons of life make different songs mean different things.”

“I think what really did it for me was ‘Bless the Broken Road,’” LeVox says. “It’s a moment in the show where just the three of us are up there. It’s a special moment in the show.”

For Rooney, it’s “I’m Moving On.” “It’s very special to me and has taken on a new life in my life. I’ve been through a lot the last five years,” says Rooney, who has been sober for three years after being arrested for DUI in 2021 and going through a contentious divorce. “These guys said, ‘Get out there and sing “I’m Moving On” by yourself.’ It’s been tough. The first couple of weekends, I was extremely nervous, but it’s very heartfelt. I mean everything I say and I just really thank God so much for my life I have right now.”

Their Backstreet Boy pals are set for a Las Vegas residency at Sphere coming up in July, and Rascal Flatts admit that sounds pretty sweet to them. “We’ve had a couple of [Las Vegas] residencies. We were three years at the Hard Rock, two at the Venetian,” LeVox says. “Setting up one time is really nice. That’s really convenient.”

“I wasn’t allowed back in Vegas for a couple of years. I think they’ve lifted that now,” jokes DeMarcus before seriously adding of Sphere dates, “I think anybody would want to play there, you know. It’s a wonderful thing, but it’s a whole other thing for us. You have to spend so much time putting creative into building the show and making sure all the content fits. It’s very expensive to build all the content.”

Rascal Flatts, who are up for group of the year at the ACM Awards for the first time since 2017, are coy when it comes to saying if they plan to release an album of new music.

“We’re trying to take it a step at a time,” DeMarcus says. “We’ve just kind of been thrown back into the deep end, but we really loved being on tour. We really loved cutting the duets record. We’re going to do some more shows this summer, and we’re still talking about what the future looks like. We’re really excited about what lies ahead for us, but we really haven’t made any definite plans yet. I would hate to say never. If we find the right kind of song and we feel compelled to cut it, we have the freedom to do that. So you never know what’s gonna happen.”