Carrie Underwood took the stage with American Idol contestant Slater Nalley to perform “I’m Gonna Love You,” her heartfelt duet with Cody Johnson, during the Idol finale on Sunday evening (May 18).

She also unveiled an epic surprise when she welcomed Johnson to the stage mid-performance.

“We just saw your face when he came out between those doors there, and it was genuine thrill and surprise,” longtime host Ryan Seacrest said to Nalley after the trio’s performance. Nalley, a high school student from Atlanta, Georgia, said he’s “such a big fan” as he shook hands with Johnson on the Idol stage.

Johnson, who recently announced his wife is pregnant with Baby No. 3, included “I’m Gonna Love You” on the deluxe edition of his album, Leather, in late 2024. Chris Stevens, Kelly Archer and Travis Denning teamed up to write the ballad, which was produced by Trent Willmon. Johnson previously shared that he would have refused to sing the song if Underwood didn’t join him on it.

“From the moment I heard this song, I heard Carrie’s voice on it. It was a non-negotiable for me; either we sing it together, or I wouldn’t sing it at all. It’s that special to me,” Johnson said in a previous statement. “Working with Carrie has been an absolute pleasure. She’s not only one hell of a singer, but she’s a class act all the way around. It warms my heart to work with someone who’s seen so much success in their career and they’re still so down to earth. I feel like this duet is going to be massive in so many ways, and I couldn’t be prouder of it!”

Underwood joined American Idol as a judge for the first time this year, marking two decades since her career-launching victory on the show. Underwood won the fourth season of Idol in 2005. She’s shared nostalgic memories throughout this season, including proof that her 2005 finale dress “still fits,” reviving one of her most iconic performances, reuniting with her fellow Idol contestants, reacting to some of her memorable Idol moments, and more. The eight-time Grammy winner congratulated the 2025 Idol winner, and beamed that she’s “so proud” of what the contestant accomplished, and said the winner will “do great things!” See the photo of Underwood with the winner below (warning: spoiler), and watch Johnson’s surprise performance here: