AceShowbiz -

Lauren Conrad is back on the single market, it has been reported. According to Life & Style, the former star of "The Hills" has ended her romance with "Dancing with the Stars" pro dancer Derek Hough after three months of dating.

Of the break-up, a friend of Lauren said, "Their relationship reached its peak. It was always casual." Agreeing that the pair's relationship never turned into a serious one, another source spilled, "She had fun with Derek - he used to send her cute texts and sing to her - but she always kept her options open."

A third source suggested that Lauren was on a rebound when dating Derek after she split from boyfriend of three years, Kyle Howard, in June, and the older brother of Julianne Hough knew it. "This was a rebound that wasn't going to last," so the source noted. "Derek never thought it would, either."

While it isn't clear when the two called it quits, Lauren was reported to be flirting with Chace Crawford when attending Matthew Morrison's Halloween party at West Hollywood's Voyeur on October 29. On the same night, Derek allegedly got cozy with "Celebrity Rehab" star Jennifer Gimenez.

Wetpaint Entertainment reported that Derek and Jennifer were first spotted together at a private Halloween party at the Standard in Hollywood, before heading to a second party at the Roosevelt hotel. An eyewitness dished, "He was all over her. He was dancing sexily with her and pulling her close. They were very touchy-feely. They looked like a lot more than just friends."