Connie Fisher has cancelled her solo tour to have surgery on her vocal cord condition.
The Sound of Music star has been told she must have the operation if she is to perform again.
Specialists said the condition, called congenital fusion anomalies, would have been with her from birth and it was a "miracle" she had ever sung.
Her 14-date Secret Love tour, which was to take her across the UK in May and June, has now been cancelled.
In a statement, her management Bedlam Management, said: "Following consultations with vocal specialists in the US it has been decided that for Connie Fisher to have any chance to perform again a procedure on her vocal cords has to be carried out.
"Connie is obviously very disappointed and upset that she is not be able to do the concert tour, but we wish her a full recovery."
The former call centre worker won the BBC talent show How Do You Solve Problem Like Maria? in 2006.
The 24-year-old played the lead role of Maria in the West End show for 15 months and released her own record, Secret Love, in February.