Two West End longrunners – blockbuster Abba musical Mamma Mia! and Guinness World Recordbreaker The Mousetrap - have extended their current booking periods.

At the Prince of Wales, Mamma Mia! has added eight months to its schedule, taking it up to 29 September 2007. The musical had its world premiere at the Prince Edward Theatre in April 1999 and, after five years, moved to the refurbished Prince of Wales in May 2004.

Set on a Greek island, the show centres on young Sophie who, preparing for her wedding day, has invited three of her mother's ex-lovers in an attempt to discover the identity of her father. Mother Donna’s former band members come along for the festivities too. The musical's original book, by Catherine Johnson, is interspersed with Abba disco classics such as "Dancing Queen", "Thank You for the Music", "Take a Chance on Me" and the title song.

The production is directed by Phyllida Lloyd and designed by Mark Thompson. Since opening in the West End, Mamma Mia! has now launched 11 productions around the world and has been seen by more than 24 million people in over 115 cities. The West End cast currently features Helen Hobson (as Donna), Joanna Monro, Geraldine Fitzgerald and Tasha Sheridan.

Meanwhile, at the St Martin's Theatre, Agatha Christie's The Mousetrap, the world’s longest-running play, has announced a new seven-month booking period, taking it up to 4 November 2006. The classic whodunit - which celebrated its 50th West End anniversary, with HM The Queen in attendance, on 25 November 2002 - has become a theatreland institution. The show originally opened next door at the Ambassadors and transferred to St Martin’s, after 20 years in its original home, in 1974.

The Mousetrap is directed by Peter Byrne. The current cast includes Kirsty Yates, Tom Sykes, John Lyons, John Fleming, Alan Freestone, Jan Waters, Adam Kay and Liz Carney.

- by Caroline Ansdell