Bono and Sean Penn whopped it up in Dublin for the American’s fiftieth birthday party.

Penn is in Dublin for his new movie ‘This Must Be the Place’ which has begun filming there.

It was also revealed that Bono's daughter Eve Hewson has signed up to play a music fan in the new film with Penn.

Eve, a newcomer to the acting scene, will play a gothic-punk-music fan in ‘This Must Be The Place’, reported the film trade paper Variety.

Bono and Penn went to O’Donoghue’s in Merrion Row a famous Irish ballad and singalong pub.

There they met music legends Finbar Furey and Dubliner’s member Barney McKenna.

Penn’s son Hopper and daughter Dylan were also along.

A source told the Irish Independent : "It was brilliant. All the old Ronnie Drew classics were sung. . . Everyone sang a song or two, including Bono."

In the new movie Penn will play an ageing rock star who becomes fixated with pursuing the Nazi criminal who tormented his father.

The film is set to begin filming this month in Ireland and the U.S.