For the Clannad album of the same name, go to The Best of Clannad: In a Lifetime."In a Lifetime" is a pop song performed by Irish artists Clannad and Bono. It was written by brothers Pól Brennan and Ciarán Brennan and produced by Steve Nye. The single was released in January 1986, and was the third single to be released from Clannad's eighth studio album Macalla (1985). It charted well in many countries including USA, Ireland, UK, Italy and Brazil.