Rhys Ifans is to step down from the production of Mood Music, which will begin previews in April at the Old Vic.
Ben Chaplin will replace Ifans who is leaving the show due to 'family reasons'.
Chaplin will take on the lead role in Joe Penhall's new play, which is directed by Roger Michell and looks at the dark side of the music industry. Chaplin's recent theatre credits include Consent and The Reporter at the National Theatre.
Further casting has also been announced for the piece, with Seána Kerslake as Cat, Pip Carter as
Ramsay, Kurt Egyiawan as Miles, Jemma Redgrave as Vanessa and Neil Stuke as Seymour joining him.
Mood Music runs as part of the Old Vic's 200th birthday season, and runs over the theatre's actual birthday on 11 May.
Mood Music runs at the Old Vic from 2 May to 16 June, with previews from 21 April.