Derek Hough and Lauren Conrad are reportedly no longer dating.

"Their relationship reached its peak. It was always casual," a source told Life & Style.

Conrad reportedly broke up with the three-time Dancing with the Stars champion -- who had denied he was even dating Conrad last month although the couple had been spotted together on multiple occasions kissing, dancing or holding hands -- because she viewed their relationship as more of a fling than anything serious.

"She had fun with Derek -- he used to send her cute texts and sing to her -- but she always kept her options open," another source told the magazine.

According to Life & Style, the former The Hills and Laguna Beach star used Hough to move on from her ex-boyfriend Kyle Howard of three years after the couple had split in June.

"This was a rebound that wasn't going to last. Derek never thought it would either," a third source added.