The Oscar-winning actor (50) is in town filming his new film This Must Be The Place alongside Bono's daughter Eve Hewson and Frances McDormand -- and he played the part of an ageing rocker to perfection.
Sporting lipstick, 'guyliner' and a wild black wig, Penn was far removed from his usual image.
Filming took place on Mount Street yesterday, with a flurry of fans stopping by to sneak a peek of the actor.
But more were interested in seeing a Georgian house in the middle of a simulated blaze, complete with the presence of the Dublin Fire Brigade.
Dublin is just one of the locations for the flick, which is being produced by Irish company Element Pictures, with New York, Detroit and New Mexico also lined up as locations for some of the scenes.