AceShowbiz -

Brody Jenner and his model girlfriend Jayde Nicole have broken up. A source close to "The Hills" actor tells Us Weekly the pair decided to go separate ways after about 15 months of dating. Reason behind their break-up remains unknown though.

Nicole, who is a former Playboy Playmate, might have hinted her separation from Jenner last Friday, December 18 when she tweeted, " 'Sometimes when you truly love someone you have to let them go.....' I never really understood that quote until now." The night before, as said by a source, the 23 year-old beauty "celebrated her break-up" with 12 of her girlfriends at Hyde Lounge in West Hollywood.

Besides, on December 19, Nicole also threw a shindig at Chicago's Manor nightclub. An insider at the venue tells Us Weekly, Nicole told everyone about her December 17 split from Jenner. "She made it sound like it was his doing, saying, 'He said he needs time to 'find himself. I don't have time for that'," says the source. "She didn't seem bothered by the recent break-up at all. She spent the entire night downing Jager shots and flirting with all of the guys."

Jenner himself, in the meantime, has been spending time in Australia for what he called as "some soul-searching." His tweet dated December 19 read, "So I decided to stay in Australia BY MYSELF!!! Hahaha this is Crazy.. Might just stay here and start a new life." The 26-year-old reality TV star has on Monday, December 21 returned to Los Angeles.