Sources tell E! News that 25-year-old Lavigne and the Hills star have been seeing each other quietly over the last couple weeks.
"They're hooking up," an insider said, "but they're keeping it low-key."
Not so low-key that they haven't been seen in public, however. The pair, who both became single late last year, were first spotted at dinner at Koi Feb. 4. According to a restaurant source, the "Sk8ter Boi" warbler and 26-year-old hunk left together in the same car and drove to club Voyeur.
They were last seen out again on Thursday, back at Voyeur, where they partied all night.
"You can tell they're into each other and both like to have a good time," another source says. "They're cute together."
Avril Lavigne and Brody Jenner aren't the only stars hitting the town. Check out more in our Celebrity Date Night gallery!