Squeal!! One Direction performed on 'X Factor' for the second time this season, bringing their brand new single 'Kiss You' to the season finale (Dec 20). The group is the biggest act in the history of the show, even though they didn't win when they appeared on the British edition. Look at 'em now! We still shake our heads in disbelief, so much so that we get a headache, over the fact that they didn't win in 2010! WTF, U.K. viewers?

They boys began the song perched on a giant pair of plastic red lips...which were painted the signature color of 1D member Harry Styles' girlfriend Taylor Swift. She was probably backstage watching every move her man made, since they are pretty much tethered to one another and can't bear to be apart. But duty called and Hazza had teenage girls that he had to make scream.

It was another flawless perf from 1D, who were dressed in black, white and grey. The dancing was perfect. The harmonies were crazy catchy. The overall staging was amazeballs.

Post-performance, Liam Payne offered up some perspective, since he and his mates had been in the same position as the finalists. He said, "You are so excited to be here at this point, you just want to win. So good luck to em."