A host of stars including The Script, Westlife and Kelis were in the Irish Republic to celebrate the birth of Guinness.
Global celebrations to commemorate the founder of the world's most famous stout - first brewed by Arthur Guinness in 1759 - kicked off in style as Snow Patrol's Gary Lightbody led the toast for Arthur's Day at 17.59pm on Thursday
About 3,000 revellers filled an old warehouse at the St James's Gate brewery in Dublin city centre to raise a glass "To Arthur" and see Westlife and the Manic Street Preachers in concert.
Actor Tim Robbins, The Script, who hail from Dublin, Kelis and Paolo Nutini were also among the scores of acts who flew in to perform surprise gigs in more than 40 venues across the country.
Unlikely pals Tim - in town with his Rogues Gallery Band - and Mark Jones, of the Clash, hugged when they met on the red carpet. The pair, who starred together in the movie Code 46, admitted they could end up side by side again jamming in a secret pub later on Thursday evening.
Kelis brought a touch of glamour to the night and revealed it had not taken much to convince her to take a break from her own tour to visit Ireland, adding: "I love Dublin, and obviously the money goes to a good cause so that's important."