Usher has been forced to pull out of his final week on Broadway with hit show Chicago after falling ill.

The R&B superstar was playing lawyer Billy Flynn in the musical and was set to leave on October 15 but has dropped out with a throat infection.

"Usher has found a new home on Broadway and is welcome back anytime," said Chicago producer Barry Weissler.

His agent Jonetta Patton said that Usher had had an amazing time on the show, adding: "He expresses his sincere apologies to all of his fans who purchased tickets to see him in Chicago this final week and appreciates all of their love and support."

He will be replaced by Christopher McDonald from Sunday.