'X Factor' Top 6: Carly Rose Sonenclar Covers Justin Bieber's 'As Long As You Love Me' (WATCH)

"The X Factor" Top 6 acts each performed two songs on Wednesday, Dec. 5.

They performed an "unplugged" Pepsi Challenge song chosen by their mentors, and their second was "America's Choice," singles that were selected by viewers at home.

The best performance of the night was undoubtedly 13-year-old Carly Rose Sonenclar's cover of Justin Bieber's "As Long As You Love Me."

Demi Lovato praised her, and likely upset "Beliebers," when she told Sonenclar, "You sang it better than Justin did."

"One of my favorite performances," said Simon Cowell.

Sonenclar's mentor Britney Spears beamed with pride while telling her, "I'm so proud of you. Each week, you make the song your own."

CeCe Frey performed her best vocal of the season. She sang Lady Gaga's "Edge of Glory", which turned judge L.A. Reid into a fan instantly. "You know what you've proved that sometimes we get it wrong because I'm starting to become a fan," said Reid. "That was maybe your best for my taste."

Viewers chose a song for Diamond White with her name on it. Her performance of Rihanna's current hit "Diamonds" was complemented with the best set production on the stage. The show's host Mario Lopez told White after her performance that her fans even requested that she sing in a "diamond," a diamond-shaped cage.

The acts gave it their best for a chance to make it to Top 4 for next week's semi-finals.

The finals, which is only two weeks away, will see two acts compete for the $5 million prize, the biggest in the history of reality television.

"The X Factor" Top 6 Results show will reveal the rankings for the Top 4 acts that will make the cut for next week's semifinals. It will air tonight at 8/7 c on FOX.