YouTube: American Idol

Thomas Rhett and Katy Perry Perform 'Where We Started' During 'American Idol' Finale

This is truly the duet we didn't expect and didn't know we needed. American Idol judge Katy Perry and Thomas Rhett joined forces on the Idol stage for the three-hour finale. The duo, whose voices go together perfectly, sang Rhett's "Where We Started" which is the title track of his new album. This was the first time the superstars performed the song live.

The singers first took the stage as silhouettes in front of a "sunrise" background on top of stairs, as we hear Rhett start off the song. The couple then reunited at the bottom of the stairs, singing the chorus together.

"Those days when you're brokenhearted/ And you're getting' knocked down/ And you say you don't know how far we're gonna go," Rhett and Perry sing. "Just look at that road and think about where we started/ Keep your eyes on me 'cause talk is cheap/ We're all we need, yeah/ Darlin', I know how far we're gonna go/ Just look at that road and think about where we started."

Earlier this year, the country singer had shared the story behind the song, saying that it was "never a plan," but he was glad it happened. Speaking with Music Mayhem, he stated a member of his team had asked him permission to send it to the pop singer to see if she would like to collaborate together.

"I was like, 'Yeah, but they're not gonna respond.'... And literally within 24 hours Katy responded and said, 'I love this. I resonate with this so well,'" Rhett stated. "When she put her vocal on it, it took her, like, two weeks. She really put a lot of time and effort into this vocal...This reminded me of how amazing a vocalist she is, and I feel like it really came to life."

Season 20 found its new winner, Noah Thompson, with Hunter Girl coming in second and Leah Marlene coming in third. Other performers included Gabby Barrett, Michael Buble, Wind & Fire, Luke Bryan, Lionel Richie, Ben Platt, and more.

Read More: 'American Idol': Country Singer Noah Thompson Wins Season 20