Are there boundaries to declaring the next "American Idol" champ? Apparently, nothing can contain the likes of Adam Lambert.

At the end of Tuesday's final performance show, Simon Cowell all but crowned the California glam rocker the winner over Kris Allen. The acoustic guitar player struggled mightily to stay in tune on "No Boundaries," co-written by judge Kara DioGuardi (CARE'-ah dee-oh-GWAR'-dee).

Lambert had no such trouble with the upper-register song. Cowell said he genuinely believed the show had found a true star in the 27-year-old theater actor.

The judges were less effusive following Allen's version of "No Boundaries" — each was noncommittal, sounding as if they were saying goodbye to the 23-year-old heartthrob from Conway, Ark.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.

Kris Allen "won" the first round of the "American Idol" finale, but the force of nature known as Adam Lambert bounced back to tie it all up.

Lambert, the guylinered glam rocker from California, is battling acoustic guitar player Allen from Conway, Ark. For his first song, Lambert sang one of his greatest "Idol" hits, wearing a long, dark coat during the brooding arrangement of "Mad World" from the cult movie "Donnie Darko."

Like the first time, it was well-received.

"I'm gonna give you an A-plus for that one dude, A for Adam!" gushed judge Randy Jackson.

Allen followed Lambert's performance with "Ain't No Sunshine." The judges' panel loved the rendition, which featured Allen on the piano.

"When your name was announced last week, I wasn't sure that America had made the right choice," he said. "I absolutely take all that back now after that performance."

With that, Cowell declared Allen the Round One winner.

The tide quickly turned — Lambert replaced his gloomy overcoat with a suit and tie for the second round of the sing-off and performed the Sam Cooke classic "A Change Is Gonna Come." The effect was soulful and over-the-top, flaunting Lambert's vocal range and theatrical delivery.

"That was the best I've ever heard you sing — ever!" crowed Paula Abdul.

Next up, Allen turned to trusty guitar for the Marvin Gaye tune "What's Going On."

Cowell disliked his interpretation, saying it sounded like "three friends in their bedroom strumming along to Marvin Gaye. ... I thought it was too laid-back for a night like this."

Round Two goes to Lambert, "a million percent," said Cowell, the de facto round-caller — though America's votes will really decide the outcome.

Lambert and Allen are slated to perform three songs a piece: a favorite performance from this past season; a tune selected by "Idol" creator Simon Fuller and a song co-written by Kara DioGuardi, the show's fourth judge.