LONDON (AP) - Even a star who has been performing for more than 50 years sometimes wants a do-over. Sir Paul McCartney sang his new song "New" at a taping of "The Graham Norton Show" in London on Thursday - then decided he wanted a second take. The former Beatle's instincts were right on target: round two had much more verve. McCartney and pop princess Katy Perry also gave a master class in songwriting at the taping. McCartney says he and late writing partner John Lennon expected to come away with a song every time they brainstormed. Perry, who says she's "an observer of life," carries around a recorder to stash away phrases that strike her fancy. McCartney later treated the audience to a rousing song not on his new album: "Lady Madonna."