06/07/2009 at 02:00 PM EDT
She was most recently linked to Star Trek
's Chris Pine, but it looks like Audrina Patridge
has moved on – and turned her attention to an ex-boyfriend.
In Las Vegas for her brother Mark's birthday, The Hills
star was spotted cuddling with and kissing her former beau, Australian BMX rider Corey Bohan.
The sexy new Carl's Jr. spokeswoman
, who wore a gold-and-black bikini, and her biker boy "were by each other's side all day and they were sneaking kisses," an observer said who saw them at Tao Beach. "He had his arm around her in their cabana and they definitely seemed together."
Later, the two were spotted at Tao Nightclub where the affection continued. In an upstairs VIP skybox Patridge spent most the night sipping vodka and sitting on Bohan's lap.
Patridge, who recently caused a stir
when she hooked up with Hills
costar Brody Jenner on the MTV show, and Bohan dated for several months last year after her on again-off again flings with fellow Hills
star Justin Bobby and a short romance with DCMA Collective partner Tal Cooperman.
With additional reporting by JENNIFER GARCIA