Connie Fisher, star of The Sound of Music, is pulling out of the West End show for two weeks after straining a vocal cord.
Connie Fisher has won several awards for her performance
The winner of BBC One's How Do You Solve a Problem Like Maria? is taking the rest on the advice of a doctor.
Ill health has caused the 23-year-old to miss several performances at the Palladium Theatre over recent months, including Monday evening's show.
Understudy Sophie Bould will fill the role of Maria until Fisher returns.
Bould usually plays the eldest Von Trapp child, Liesl, but has been acting as stand-in during Fisher's absence.
A spokesman for the production said: "Through a desire not to let the public down, Connie Fisher sang through a heavy cold which has caused a vocal injury.
"The vocal cords are a muscle like any other and, as in the sporting world, when injured they require complete rest to recover."
He added: "We are very lucky that, in Connie's absence, the role of Maria will be covered by Sophie Bould, who has been receiving standing ovations for her portrayal of Maria."