Although she walked the red carpet solo at the L.A. premiere for her film Push in Westwood, Belle, 22, was later joined inside the theater by Jonas, 19.
"Once the lights in the theater went down, Joe snuck in and sat right next to her," an eyewitness tells E! of the rumored couple. "After the credits rolled, they left in a rush holding hands."
Last fall, Belle starred in the Jonas Brothers music video, "Lovebug," where she played the guys' love interest. Apparently, it wasn't all playacting.
By November, Joe and Camilla were being photographed together in Cabo San Lucas, Mexico, celebrating Nick Jonas' birthday with family friends.
While Belle has recently been seen out with both Joe and Twilight star (and pal) Robert Pattinson, it seems she wants Jonas by her side when the lights go down.
"Camilla does not comment on her personal life," her rep Brad Cafarelli tells E!
And Jonas' rep has so far also declined to comment. Stay tuned.
—Reporting by Aly Weisman