EXCLUSIVE: Keith Urban Reveals New Details on His Carrie Underwood Duet on 'Ripcord'

The 'American Idol' judge also shared his thoughts with ET on the show's final two, who he calls, 'Incredible singers.'

With his time as a judge on American Idol coming to an end, Keith Urban is looking forward to the release of his upcoming album, Ripcord -- which, the country crooner recently revealed, contains a collaboration with former Idol winner Carrie Underwood.

Speaking with ET's Sophie Schillaci after Part 1 of the Idol series finale on Wednesday, Urban revealed a few more exclusive details about the star-studded duet.

"I wrote this song with this guy called Busbee. The song is called '[The] Fighter.' I would say it's a call-and-response song between a guy and a girl and Carrie's on that song with me," Urban shared.

WATCH: Keith Urban Reveals Carrie Underwood Duet on New Album 'Ripcord

Urban teased that he'll be performing on Thursday's two-hour grand finale, but fans probably won't be seeing Underwood take the stage to premiere the new track.

"[I'm] singing a song with somebody who I toured with many years ago and it'll be a song that everybody knows and that's all I can say," Urban hinted.

While he didn’t name names, Urban did tour with Underwood in 2008, promoting his album, Love, Pain and the Whole Crazy Thing, and her album, Carnival Ride.

The 48-year-old singer also opened up on Idol's two finalists, La'Porsha Renae and Trent Harmon, who delivered some of the season's best performances Wednesday night.

WATCH: 'American Idol' Finale: La'Porsha Renae Tears Up, Dedicates Performance to Baby Daughter

"In that first half, La'Porsha sang [and] she absolutely had it," Urban explained. "Then Trent came out and completely owned and hands down, made it an incredibly tough call."

"It'll be interesting to see what happens tomorrow night," he added. "I'm sure whoever wins it, it won't be a landslide because they're two incredible singers."

After Idol comes to a close, it seems Urban will have a bit more time to spend with his wife, Oscar winner Nicole Kidman, and their two daughters -- Sunday Rose, 7, and Faith Margaret, 5.

WATCH: Keith Urban Reveals the Secret to a Successful Hollywood Marriage: 'Keep Dating'

Recently, Kidman, 48, was photographed looking absolutely amazing in a bikini on the beach. When asked if there were "days where you just look at her and you're like, 'How did I get so lucky?,'" Urban laughingly replied, "Of course, yeah."

Kidman and Urban recently spoke with ET on the red carpet at the Academy of Country Music Awards where she revealed that she "definitely danced" to her husband's collaboration with Pitbull on the track "Sun Don't Let Me Down," off Urban's upcoming album.

Check out the video below to hear more about some of the dynamic duets fans can expect from Ripcord, out May 6.