You'll Never Guess Who Joined Robert Pattinson for Drinks
updated 11/29/2012 AT 12:15 PM EST
•originally published 11/28/2012 AT 05:30 PM EST
Not long after their arrival, though, the men were joined by a group of friends – including singer M.I.A., who capped off her signature eclectic look with an oversized hat.
Pattinson, in a jacket (but not his usual baseball cap), "looked happy and relaxed," a source tells PEOPLE. Though he frequently left his pals for breaks on the smoking patio, "he only paid attention to his guy friends, laughing and letting loose a little bit," the source continues. After about an hour, the whole party said goodbye and left the venue. – Jennifer Garcia