We know what you're thinking, but not so fast...

Kate Hudson rubbed elbows with boy toy Nick Jonas' older brother Joe last night at a birthday party for CAA power agent Cade Hudson at The Palm in Beverly Hills, and we're dying to know if the two are getting closer in the wake of the actress' romance with the youngest Jo Bro. It's kinda like hanging out with your new brother-in-law, except you're old enough to be his mom!

The Almost Famous starlet and the "Jealous" crooner have reportedly been hooking up since the summer, and right when we thought they had cooled off, they were spotted getting cozy on a ski vacation in Mammoth just last week. Oh la la!

Kate and Joe weren't the only big names in the house yesterday evening, though! Gwyneth Paltrow, Paris and Nicky Hilton, Rachel Zoe, Seth McFarlane, and Ryan Phillippe were just a few of the other celebs in attendance.

We wonder if Joe is at all jealous that his sibling snagged a bona fide hottie?!