Pop star George Michael has been told by doctors not to speak for two weeks after undergoing an operation in a private London clinic this week to remove a cyst from his vocal chords.

The 25-year-old singer's current world tour came under threat last week after he developed voice problems."The operation was very successful, but he must not speak at all for a fortnight. After that he will fully recover and the doctor said he will sing like a bird when he is well again," a friend said.

Michael was expected to remain hospitalized for a few days and then fly to a secret hideaway.