SHE is used to writing weepy romances, but author Cecelia Ahern is about to immerse herself in the world of scarf-loving time travellers, Daleks and space pigs.
The mum-of-two, who created popular ABC comedy Samantha Who? starring Christina Applegate, is one of several high-profile writers to write a short adventure story for Time Trip, the Doctor Who 50th anniversary e-book.
Cecelia announced the news on Twitter. "So excited & honoured to announce I've written a Doctor Who story for Time Trips, celebrating the 50th anniversary," she wrote .
Other contributing authors include Edie Investigates writer Nick Harkaway, Joanne Harris – the brains behind Chocolat – Original Bliss author AL Kennedy and best-selling writer of the Black Magician Trilogy Trudi Canavan.
Each of the authors will write a 10,000-word piece, with BBC Books selecting an eclectic mix of names to to ensure they get a variety of genres, from romantic fiction, to high fantasy and classic thrillers.
BBC Books plans to release the first in the Time Trips series at the end of the year. A selection of the stories will be printed in regular format in 2014.
Cecilia is currently in Germany promoting her book How To Fall In Love. Bertie Ahern's daughter is a big hit with audiences over there – two of her short stories have been made into TV films this year alone.
But Cecilia (32) said her popularity there was a mystery to her. "Out of all the markets, it's the one that seems to be the biggest," she added.
The writer is one of Ireland's most successful. In 2007, her novel PS I Love You was transformed into a big budget rom-com starring Gerard Butler and Hilary Swank.
And Love Rosie, based on heart-warming story Where Rainbows End was filmed in Dublin this summer. and is due out next year.
The mum-of-two has also written a children's book about two snowflakes that are exactly the same.
"You know the way everyone says no two snowflakes are the same?" she asked. "Well, this is about two snowflakes that do look the same. That's what makes them unique."