Lydia White is to join the Southwark Playhouse production of The Last Five Years.
White will stand in for Molly Lynch who has been forced to step back from the show due to illness.
A statement shared by the show on social media read: "Unfortunately Molly Lynch has been signed off with illness but we're thrilled that the brilliant Lydia White will be stepping into the role of Cathy.
"We hope to welcome Molly back soon and wish Lydia the best for her first performance [March 12]."
White joins Oli Higginson on the cast of the acclaimed revival.
The sung-through piece will see White and Higginson in the roles of Cathy and Jamie respectively, with the musical telling the story of the couple's five year relationship.
The new production is directed by Jonathan O'Boyle with musical direction and orchestrations by George Dyer.
Featuring a unique actor-musician staging, choreography comes from Sam Spencer-Lane with design by Lee Newby, lighting by Jamie Platt and sound from Adam Fisher.
The Last Five Years is currently scheduled to play at Southwark Playhouse through to March 28.
Tickets and more details are available online here.