Katharine McPhee is to leave the West End cast of Waitress on June 15.
She has been with the production since it began playing at the Adelphi Theatre in March.
Casting for the role of Jenna after McPhee leaves will be announced soon.
The musical is written by Sara Bareilles, and is directed by Diane Paulus.
It has a book by Jessie Nelson and choreography by Lorin Latarro.
The musical is booking until October 19 and also stars David Hunter, Laura Baldwin and Marisha Wallace.
Waitress is produced by the American Repertory Theatre, Barry and Fran Weissler, Norton and Elayne Herrick, Alecia Parker, David I Berley, Feste Investments BV, Peter May, Evamere Entertainment, Tamar Climan, Michael Roiff, Ken Schur, 42nd.Club, Square 1 Theatrics, Jam Theatricals, Adam Blanshay Productions.