Bradley Cooper's uncle taught De Niro Philadelphian

Bradley Cooper was on the "Late Show with David Letterman" to talk about his new flick, "The Silver Linings Playbook" Monday night.

Cooper told Dave and nice little anecdote about his Uncle Ernie, a heating and air conditioning repairman, teaching Robert De Niro, one of the greatest actors of all time, how to speak Philadelphian.