Why Britney Spears Can't Be Like Kim Kardashian

Elle covergirl opens up about her fiancé and how she is 'a tomboy at heart.'

A leather-clad Britney Spears covers the October issue of Elle magazine, and inside she's not only opening up about her relationship with her fiancé, talent agent Jason Trawick, but also her feelings about celebrity life.

"I love my jeans and my sweats — I'm really just a tomboy at heart," she says in the new issue. "So it's really hard for me to be like Kim Kardashian and be makeup and hair ready every time I go out of my house. I'm not a believer in that, you know?"

Spears, who is no stranger to getting caught without her makeup done by the prying lens of the paparazzi, added that she doesn't much care about what people think about her anymore. "I guess I've been under the microscope so long that I don't even pay attention to the nonsense anymore," she said. "I gave up getting upset about things people make up about me a long time ago."

While she may not care about the speculation surrounding her personal life, she wanted to be a bit more discreet about the origins of her relationship with Trawick, who appears alongside her in the issue's photo spread. Trawick asked Spears to marry him last December. When the magazine asked the couple how they took their marriage from professional to romantic, Trawick was interrupted from spilling the details.

"It was one of those things where she moved, like, turned around, so we were face-to-face and then..." he explained, before she cut him off, adding, "OK, that's enough information, sweetie. It was sweet, just say that."

Spears will kick off her new gig as a judge on the "X Factor" on September 12. She joins the show along with VMA pre-show performer Demi Lovato for the show's revamped second season.

Before the show's premiere on Fox next week, fans can check out Lovato when she takes the stage during the VMA pre-show at the 2012 MTV Video Music Awards tomorrow at 7 p.m. ET/PT ahead of the main show, which goes live at 8 p.m. ET/PT.