The producers of Whatsonstage.com Award-winning musical Matilda have announced Bertie Carvel will play his final performance as Miss Trunchbull on Sunday 1 July 2012.

Also announced were the departures of Paul Kaye and Lauren Ward, replaced by Hayley Flaherty and Steve Furst in the roles of Mr Wormwood and Miss Honey. Matilda has also extended its West End booking period with tickets now on sale through to 17 February 2013.

There will also be changes to the four young actors who play the show's title role with Isobelle Molloy (currently playing Amanda Thripp) and Jade Marner joining current cast members Cleo Demetriou and Eleanor Worthington Cox.

Kerry Ingram, who has been with the show since the show's 2010 Stratford inception, and Sophia Kiely will leave the show in mid-April. Hayley Canham will also join the company in the role of Matilda from mid-August.

A replacement for Carvel as the hammer-throwing headmistress, Miss Trunchbull, is still to be announced.

Josie Walker will continue in the role of Mrs Wormwood along with the rest of the adult cast which including: Marc Antolin, Verity Bentham, Peter Howe, Michael Kent, Melanie La Barrie, Matthew Malthouse, Alastair Parker, Nick Searle and Emily Shaw who also appeared in the original production in Stratford.

The adult cast also includes: Matthew Clark, Katy Monk, Rachel Moran, Leanne Pinder, Lucy Thatcher, Tim Walton and Gary Watson.

Three teams of young performers currently play the roles of Bruce, Lavender, Amanda, Nigel, Eric and the other pupils at Crunchem Hall.

Matilda the Musical picked up four awards at the 2012 Whatsonstage.com Awards including Best New Musical, Rob Howell for Best Set Designer, Peter Darling for Best Choreographer and Tim Minchin for the London Newcomer of the Year.

The show received a total of nine nominations including Best Actress in a Musical for all four of the young actresses playing Matilda, Bertie Carvel for Best Actor in a Musical, Lauren Ward for Best Supporting Actress in a Musical, Paul Kaye for Best Supporting Actor in a Musical and Matthew Warchus for Best Director.

The musical, which premiered in 2010 at the RSC's Courtyard Theatre in Stratford-upon-Avon, is currently nominated in every category for which it is eligible at this year's Olivier Awards, with a total of ten nods. The results of this year's Oliviers will be announced in a ceremony at the Royal Opera House on 15 April 2012.

Adapted from Roald Dahl’s 1988 novel, Matilda The Musical is written by the playwright Dennis Kelly, with music and lyrics by the Australian comedian, musician and composer Tim Minchin, and direction is by Matthew Warchus.

The production is designed by Rob Howell, with choreography by Peter Darling, orchestrations, additional music and musical supervision by Christopher Nightingale, lighting by Hugh Vanstone, sound by Simon Baker and special effects and illusions are by Paul Kieve.