Who will be eliminated from the X Factor semi-final results tonight? Click here to see the live elimination show at 8/7c on FOX tonight.

"The X Factor" semi-final performances took place Dec. 12.

The top 4 acts performed two songs each last night - a Contestants' Choice song selected by viewers at home and a song chosen by their mentor.

Carly Rose Sonenclar, Tate Stevens, Emblem3, and Fifth Harmony sang their hearts out for a spot on next week's X Factor finales.

The highlight of the night came from 13-year-old frontrunner Carly Rose Sonenclar. She sang and played the piano to the John Lennon classic "Imagine."

"What I love is that you've taken your artistic credibility up one notch by playing the piano," said, judge L.A. Reid, while admitting that he was impressed that she tackled such a beloved yet difficult song to accomplish. "You always go in and find that [high] note, don't you?" he added.

The other highlight of the night came from one of Simon Cowell's two groups that are still in the running, Emblem3.

The boy band performed an impressive spin on Peter Frampton's "Baby I Love Your Way" for their Contestants Choice song. The rap and reggae-inflicted take on the Frampton classic inspired Reid to call it their "$5 million moment." "That is the first time I really saw you as recording artists," he added.

"If this doesn't get you into the final, nothing will," their mentor Cowell said proudly.

Cowell chose the Beatles' classic "Hey Jude" for their second song performance. Reid commented that doing a Beatles song was very "presumptuous," but added they are "teen heartthrobs" like the Beatles.

Spears called an "A-level performance."

"Guys, I just feel so proud of what you've achieved here tonight" Cowell said of his group, adding that they "nailed" both songs.

"The X Factor USA" co-host Khloe Odom couldn't contain her disbelief that the season is coming to an end. "This is crazy!" she said. "I can't believe the finals are next week!"

During the "Live Results" show which will air tonight, only three acts will advance to next week's finals. There will not be a sing-off between the Top 4 and none of the judges get to pick their favorite acts during the "Live Results" episode, said Lopez. The elimination will be based purely on viewer voting.