Britney Spears looked HAWT in a form-fitting red dress and her hair fixed in a sexy, voluminous, librarian-style bun as she and Simon Cowell hit the promo circuit and went on 'Ellen' to talk up the season premiere of 'X Factor,' which is tomorrow, Sept. 12. She also danced Gangnam style, but that's a whole other deal!

In a quick backstage clip, Ellen asks Brit Brit if a tiny tee belongs to one of her sons, then Simon storms through and steals it.

While on the couch for a chat, Brit reveals she took the judging gig since she and Simon have the same makeup artist and the MUA told Brit how much fun she had on the set of the show. That's when Mr. Cowell knew he had to turn on the charm over the course of three calls with Brit, who said, "I couldn't resist."

When Ellen asked the 'Toxic' singer if it was hard for her to be critical, Cowell interjected, "No," answering for Brit. She argued, "I used constructive criticism," to which Simon claimed she said "no" to contestants faster than anyone he knows.

Simon admitted that Khloe Kardashian is a favorite for the hosting gig, too. Really? Really.

Brit looks disgusted when talk turned to 'The Voice,' which added a third show this week against the 'X Factor' premiere, which we think is overkill. So does Simon, who said it messes with the audience. He also said that 'The Voice' heard how good the first ep is, especially with Brit Brit's debut, and got scared and employed this shady tactic.

Tune in tomorrow to see Brit as an 'X Factor' judge. We. Cannot. Wait.

Watch Britney Spears + Simon Cowell Talk Who's a Nicer Judge

Watch Britney Spears + Simon Cowell Talk Frustration With 'The Voice'

Watch Britney Spears + Simon Cowell Talk New Host