Carrie Hope Fletcher has been announced as a guest performer at An Evening with Jason Robert Brown in March.
Brown, the composer of shows including The Bridges of Madison County and Parade, will appear as part of a strand of events called Sunday Encounters at the Haymarket. His concert will take place at the Theatre Royal Haymarket on March 31.
Fletcher, who appeared in Heathers at the theatre, is the first of a number of special guests to be announced for the event.
The show will mark the first time the pair have performed together on the London stage.
Fletcher was also recently announced as part of the cast for a special concert production of Les Miserables at the Gielgud Theatre.
The show is produced by Fane Productions.
Other events in the series include Patti LuPone in conversation with Edward Seckerson and Kerry Ellis: An Evening of Music and Memories.