Two long-running West End musicals - Mamma Mia! and Chicago - have both announced major cast changes and six-month extensions to their booking periods.

At the recently refurbished Prince of Wales theatre (See News, 14 May 2004), where it moved to in May after five years at the Prince Edward, blockbuster Abba musical Mamma Mia! is now booking up 25 April 2006, with tickets for the new period going on sale from 14 March.

Set on a Greek island, Mamma Mia! centres on a young Sophie who, preparing for her wedding day, has invited three of her mother's former 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.

From 7 March, Sophia Ragavelas (Les Miserables, Brighton Rock) will take over as Sophie Sheridan. Vivien Parry continues as mother Donna (though Lucy Harris will now play the role at certain performances), with Lara Mulcahy and Kim Ismay as her friends Rosie and Tanya. The cast also features Simon Slater (as Sam), Martin Ball (Harry), John Alistair (John) and Fergus Marsh (Sky).

At the Adelphi Theatre, where it opened in November 1997, Chicago is now booking until 3 December 2005. From next Monday 28 February 2005, Anna Montanaro and Zee Asha will return to the roles of Velma Kelly and Mama Morton, while Robert Hands (who previously starred in Mamma Mia!) will take over as Amos Hart. Jill Halfpenny and Michael French will continue to star as Roxie Hart and Billy Flynn.

Chicago, based on the play by Maurine Dallas Watkins, has a book by Fred Ebb and Bob Fosse, music by John Kander and lyrics by Fred Ebb. Scenic design is by John Lee Beatty, costumes by William Ivey Long, lighting by Ken Billington and sound by Rick Clarke. The production is choreographed by Ann Reinking in the style of Bob Fosse and directed by Walter Bobbie. In 1998, it won the Olivier for Outstanding Musical Production and the Critics Circle Award for Best Musical.

- by Terri Paddock