Sara Bareilles and Gavin Creel are to join the cast of Waitress in London's West End.
The pair will appear in the roles of Jenna and Dr Pomatter from January 27th.
Bareilles wrote the score for the musical and previously appeared in the lead role on Broadway alongside Creel earlier in 2019.
They will takeover Lucie Jones and David Hunter in the roles in London through to March 7. Jones and Hunter will return to the roles of Jenna and Dr Pomatter on 9 March.
It'll be Bareilles' West End debut with Creel previously appearing in the London casts of Mary Poppins and The Book of Mormon.
Bareilles said: "I am so excited to be using my passport in the New Year because I am coming to the West End to play Jenna in Waitress The Musical.
"I am coming to London and I am bringing one of my very best friends, Mr Gavin Creel who you would know from the original cast of the Book Of Mormon.
"We're going to join the cast of Waitress at the Adelphi Theatre starting January 27th for six weeks only so get your tickets and come and see us down at the diner."
Waitress tells the story of Jenna a waitress and expert pie-maker who dreams of a way out of her small town and rocky marriage.
Alongside Bareilles' score, the hit musical features a book by Jessie Nelson and direction by Diane Paulus.
Together with Jones and Hunter, the current West End cast features YouTuber and Strictly Come Dancing finalist Joe Sugg appearing in the role of Ogie with Laura Baldwin as Dawn.
Waitress in London recently extended its booking period at the Adelphi Theatre until March 28, 2020.
The standard performance week is Monday to Saturday at 7:30pm with Wednesday & Saturday matinees at 2:30pm.