Brody & Avril Lavigne Ridin' Dirty

2/17/2010 10:45 AM PST
Avril Lavigne got nice and cozy in the backseat of a car last night -- Brody Jenner's car.

She's still not officially divorced from hubby Deryck Whibley, but it seems Avril is already on the rebound -- 'cause let's get serious ... does anyone really think Brody's in it for the "friendship?!"

Didn't think so.