By the Daily Mail
If he's not careful, hard-bitten actor and director Sean Penn will earn himself a reuptation for being a lightweight.
He celebrated his 50th birthday with a lunch in Dublin with local boy Bono but skipped out of proceedings after a mere two hours.
However, in true Irish fashion, his U2 frontman friend felt able to carry on the revelries, emerging from the restaurant an impressive six hours later.
The duo were enjoying lunch together at Marco Pierre White's Steakhouse and Grill in Dublin, ahead of the actor's landmark birthday tomorrow.
However, when Penn emerged he didn't look like he was celebrating much at all, with his head down and a scowl on his face.
Bono was a different matter though.
When the U2 frontman left it was night time and he looked a little worse for wear as he clung onto a lamp post at one point for some much needed support.
It seems it was a weekend of celebrating - the night before Bono had organized a party for Penn at Samsara Bar.
Penn's teenage son Hopper and daughter Dylan, Bono's daughter Eve Hewson and actor Kris Kristofferson were amongst the guests.
The Belfast Telegraph reports that the party carried on to O'Donohue's pub on Dublin's Merrion Row, where Penn and Bono had a singsong with music legends Finbar Furey and Barney McKenna.
According to a source: 'It was brilliant. All the old Ronnie Drew classics were sung....everyone sang a song or two, including Bono.'
Penn is currently in Dublin filming This Must Be The Place, in which he plays an aging rock star who becomes fixated with pursuing the Nazi criminal that tormented his father.
The movie also stars Bono's daughter Eve, who plays a gothic-punk music fan.
Â© Associated Newspapers Ltd