The 52-year-old, who had a stormy four-year marriage to the singer from 1985 to 1989, attended her show and onlookers said Penn was quite impressed with her raunchy stage performance, reported Showbizspy.

Penn also went backstage to congratulate Madonna after her performance and witnesses said he was "like a teenage boy meeting his idol. It was amusing, and kind of cute."

Sean Penn and Madonna