Cecelia Ahern was born on September 30, 1981 in Dublin, Ireland. She is the daughter of the former Irish Taoiseach Bertie Ahern. On 14th December 2009 it was announced that Cecelia had given birth to her first child with partner David Keoghan, a girl named Robin. She was secretly married on 11 June 2010 in County Kildare, Ireland. Her older sister, Georgina Ahern is married to Nicky Byrne of Irish pop group Westlife. Cecelia was a member of the Irish pop group Shimma who finished third in the Irish national for the Eurovision Song Contest in 2000. She attended Griffith College Dublin and obtained a degree in Journalism and Media Communications.

Cecelia Ahern wrote her first novel, PS. I Love You when she was twenty-one. It was published in 2004, the number 1 bestseller in Ireland for 19 weeks and sold in over forty countries. The book was adapted as a motion picture directed by Richard LaGravenese and starring Hilary Swank and Gerard Butler and released in 2007 in the United States.

Her second book, Where Rainbows End (US title: Love, Rosie or Rosie Dunne) won the German CORINE Award in 2005. She contributed with short stories to charity books and is also the co-creator and producer of the ABC comedy Samantha Who?.

Her other works include If You Could See Me Now (US title: A Silver Lining), A Place Called Here (US title: Theres No Place Like Here) Thanks for the Memories (US title: Desire Lines) The Gift The Book of Tomorrow.