'X Factor': LeRoy Bell and Stereo Hogzz in lip-synch controversy

"The X Factor" contestants need a lot of ability to advance in the reality competition. They must be able to sing, perform and dance. But one thing judges may want to look into adding for next year are lip-synch skills.

During Thursday's elimination episode of "The X Factor," the twelve remaining acts did a group number of the David Guetta and Usher song "Without You." Everything went fine until LeRoy Bell forgot to pretend he was singing. Matters got worse when some members of the Stereo Hogzz sang but didn't hold the microphones to their mouths.

A FOX spokesperson tells TMZ that group numbers are "pre-recorded...This is also no different to what other competition shows do for ensemble performances."

This isn't the first time that "The X Factor" has tinkered with the voices of their contestants. In the U.K. edition of the series, show producers admitted in 2010 that they use Auto-Tune to tweak a singer's performances explaining that it's all in the name of television.

Here's the full video of the performances. The gaffes are so obvious, even Ashlee Simpson would recognize them.