Punk icon Patti Smith joined U2 on stage on Monday night at New York's Madison Square Garden to sing a duet with Bono on a version of John Lennon's 'Instant Karma'.
Smith was opening for U2 during the two nights they played Madison Square Garden on this part of their Vertigo tour.
Bono praised her and guitarist Tom Verlaine as "idols" at the opening of U2's set.
He also thanked Smith "for being a great inspiration to four lads from Dublin twenty-five years ago."
U2 now travel to Canada for a handful of concerts before they return to complete their dates in North America before Christmas.
