"Ever since Nicole broke up with [race-car driver Lewis Hamilton], she's been hanging out with Derek," a friend of the dancer tells Life & Style. "He 100 percent acts like he's her boyfriend."
Even in front of Lauren! On Nov. 10, Derek, 26, was all over Nicole, 33, right in front of his ex, 25, at the opening of Greystone Manor Supperclub in LA. "He didn't leave Nicole's side," says a partygoer. "Lauren tried her best to avoid him."
After dating for only three months, Lauren and Derek called it quits in early November. Shortly after, Derek began romancing Nicole, with whom he'd danced -- and won -- during season 10 of Dancing With the Stars.
Photo Credit: ABC