Justin and Kelly Perform on GMA

Justin Guarini and Kelly Clarkson of American Idol fame say they're happy to share the spotlight in their new movie and on stage for their Good Morning America summer concert series performance.

The pair performed live on GMA from New York City's Bryant Park. They both performed separately before coming together for a passionate performance of "Timeless," a song from their upcoming film, From Justin to Kelly.

Guarini, 24, says he and Clarkson, 20, sometimes can't believe how quickly they both found success after American Idol. He says it sometimes feels as if their time on last year's competition was actually years ago.

"We often say we feel like we're 30. But it's just the way it's happened for us," Guarini said on ABCNEWS' Good Morning America.

Clarkson's first CD, Thankful, has gone platinum and Guarini's first CD, titled Justin Guarini, was released just this week.

The two teen idols also performed songs from their own CD's. Clarkson sang "Miss Independent," while Guarini sang "Sorry."

Guarini, of Doylestown, Pa., and Clarkson, of Burleson, Texas, both attended recent screenings of the complete movie at theatres in their hometowns.

Clarkson said it was a real shock to see her own face on the big screen.

"It was strange," Clarkson said.

The movie, a musical about two students who fall in love while on spring break in Florida, is set to open nationally on June 20.

Clarkson was given the title American Idol and a $1 million record deal when she received more votes that Guarini during the show's Sept. 4 finale. But Guarini also came out a winner when he was signed to a management contract by the show's executive producer, Simon Fuller, of 19 Entertainment.