The musical revival has also extended its run at the Theatre Royal Drury Lane for a final time.
Bonnie Langford, whose numerous credits include Gypsy, Chicago, and Cats, will join the London company of 42nd Street September 3 in the role of Dorothy Brock.
Langford, most recently seen in BBC's Eastenders, will star alongside Tom Lister as Julian Marsh, Clare Halse as Peggy Sawyer, and Ashley Day as Billy Lawlor.
The homage to the world of musical theatre has extended its run at Theatre Royal Drury Lane for a final time through January 5, 2019. Following the musical's run, a refurbishment of the theatre will commence.