An unlikely pair -- Fergie and Quentin Tarantino -- bonded over birthday cake in Vegas Thursday night. She's 33; he's 45. But if trying to still be hip counts for anything that QT gets mad points!

Fergie and QT were at the Revolution Lounge and Jet nightclub at the Mirage for their big birthday blow-out emceed by Jeff Beacher. Daryl Hannah and Kid Rock were a couple of the invitees on hand.

So how come Fergie and Quentin are chilling together at all, much less celebrating their birthdays together? Well, the two met while QT was shooting Grindhouse, a movie co-written by Robert Rodriguez who directed Fergie in Planet Terror - so 'ol Rob brought 'em together.

Happy birthday, you guys!