Sam Smith undergoes successful vocal cord surgery

Sam Smith has undergone successful vocal cord surgery at a Boston hospital.

The Grammy Award-winning singer was treated for recurrent vocal cord bleeding, which can make it difficult to speak and almost impossible to sing, at Massachusetts General Hospital.

A statement from the hospital said the singer - who turned 23 yesterday - was expected to make a full recovery.

Smith took to Twitter in the early hours of Wednesday to thank fans for the birthday messages.

The British singer was forced to cancel the rest of his Australian tour in April because of the issue, telling fans at the time that it "killed" him having to pull out.The surgery was performed by Dr Steven Zeitels, who has performed the same procedure on Steven Tyler, Lionel Richie and Adele.

Smith won four Grammy Awards in February, picking up prizes for his song Stay With Me and album In The Lonely Hour.

His next live show is scheduled for July 18.