Is Camilla Belle Stepping Out On Joe Jonas -- With 'Twilight' Star Robert Pattinson?!

Belle and Pattinson were photographed together at an afterparty last month and were seen hanging out at the 'Twilight' premiere.

Is Camilla Belle stepping out on Joe Jonas already? And with "Twilight" star Robert Pattinson, no less?

Only a week after word spread that Jonas — who may or may not have cheated on the artist with the nation's best-selling album, Taylor Swift — and Belle were dating, and days after pictures surfaced of the two vacationing in Mexico, rumors are flying that his "Lovebug" co-star has been seeing other guys, like the aforementioned Pattinson.

Belle was spotted on the carpet, all by her lonesome, for the "Twilight" premiere in Los Angeles earlier this week. Love interest Jonas was nowhere in sight, and Belle was seen hanging with Pattinson throughout the night and at the movie's afterparty.

This isn't the first time that Belle and Pattinson were seen together. Back in October, the duo posed for pictures together at a Hollywood Film Festival Awards afterparty, looking quite happy to be seen together. (The Los Angeles Times also reported that Belle is rumored to be dating Pattinson's pal, actor Tom Sturridge, but we're having a hard enough time keeping track as it is.)

Unlike Pattinson and Belle (well, apart from the Mexican vacation photo), Jonas and Belle have not made any public appearances as a couple. "They are not public about it but they've just been hanging out with their friends and Joe's brothers," a source told People last week. "They are very private about it."

Despite the rumblings of a romance with Belle, in a new interview set to air on "Ellen" Friday, Pattinson insists that he's single, according to

Pattinson told Ellen DeGeneres, "I am, but no one else seems to get into a relationship with me. It's really strange."

He jokingly added, "People [such as fans] like screaming at me. Actually, they like screaming at me in relationships as well. No one wants to commit."