Fast & Furious 6
Near the end, Tyrese Gibson tells Dwayne Johnson, “Save the baby oil.” and Johnson improvised, “You better hide that big-ass forehead.”
That comment was so unexpected that Ludacris could not help but laugh in the middle of the scene. The nature of the moment made it seem like they all had a history together and it was left untouched.
I live near very near to LA; I know people who work in the film industry. Around here, a lot of people would have firsthand knowledge of that sort of thing, so it wouldn't be unusual to hear from someone who knows something such as that.