Born Cecelia Ahern on September 30, 1981 in Dublin, Ireland. She is the daughter of the former Irish Taoiseach Bertie Ahern and currently dating David Keoghan, an actor who was formerly an Irish hurdler and Olympic hopeful. Her older sister, Georgina Ahern is married to Nicky Byrne of Irish pop group Westlife.
In 2000, she was part of the Irish pop group Shimma, who finished third in the Irish national final for the Eurovision Song Contest. Before starting her writing career, she obtained a degree in Journalism and Media Communications from Griffith College Dublin.