'X Factor' Performance Finale Features Guest Duets

R. Kelly, Avril Lavigne and Alanis Morissette join contestants on their final night of performances.

At the outset of Wednesday's (December 21) 90-minute "The X Factor" performance finale, which pitted three singers — Josh Krajcik, Chris Rene and Melanie Amaro — against one another for a $5 million recording contract, judge Simon Cowell predicted, "I think this is going to be the closest final we've ever had."

By the end of the penultimate show, Cowell made it clear who had his vote to win, and unsurprisingly, it was the singer he mentored in the race, Melanie Amaro. Following Amaro's second song, a rendition of Beyoncé's "Dreamgirls" ballad "Listen," Cowell gave up all pretense of objectivity and threw his weight behind the singer, whom he at one point cut from the competition before reconsidering and allowing her back in after making a personal visit to her home.

"I brought this show to America because I believe some of the greatest singers in the world are from this country, and you just proved that," he told the 19-year-old from Sunrise, Florida. "I think you, based on that performance tonight, to me, should be the winner of 'The X Factor,' because you're going to represent this country all over the world."

Earlier in the show, Amaro performed a duet of "I Believe I Can Fly" with R. Kelly, which marked Kelly's first performance since undergoing throat surgery earlier this year. Amaro held her own with the singer, but Kells stole the spotlight with his effortless vocal gymnastics, on what was called his first-ever duet of his 1996 smash. For his part, Kells called Amaro "unbelievable," and said, "There's no doubt in my mind this girl is on her way to the moon." While L.A. Reid criticized Amaro for not performing well in the song's key, Cowell backed her 100 percent, calling the performance "close to godly."

Chris Rene, a 28-year-old from Santa Cruz, California, shared the stage early on with Avril Lavigne, as the two performed Lavigne's hit "Complicated" together, complete with a new rap from Rene. Rene's second song was "Young Homie," a song he penned and sang during the audition process and again on the November 22 episode, when he mixed it with the Beatles' "Let It Be."

He earned high marks from the judges, with Paula Abdul dubbing his "Young Homie" performance "magic," while calling Rene — who celebrated his eighth month of sobriety on Tuesday — the "consummate singer-songwriter-performer." "You make everyone fall in love with you!" she beamed. Cowell called him a "brilliant" performer, adding he's a "true gentleman" and a "really nice guy."

Josh Krajcik, a 30-year-old self-described "burrito slinger" from Columbus, Ohio, opened the show with Alanis Morissette, as the two took on her 1998 hit "Uninvited." Krajcik was visibly nervous while sharing the stage with Morissette but was much more in his element during his second song, when he stripped away all the fancy production cues and did "At Last" alone with his guitar. That performance was hailed as a return to form from the judges.

"This is what we liked about you in the first place," said Cowell, while Krajcik's mentor, Nicole Scherzinger, praised his consistency throughout the competition. "You have delivered in every single performance," she told him.

The winner will be crowned on Thursday's two-hour finale, which is set to feature appearances by Justin Bieber, 50 Cent, Leona Lewis, Pitbull and Ne-Yo.

What did you think of the "X Factor" finale? Sound off in the comments!