The singer/actress who played Carole King in a stage show based on her life was stunned when the veteran star attended a performance incognito and then whipped off her disguise midway through.

Jessie Mueller won a Tony Award for playing the music legend in Beautiful - The Carole King Musical after it opened on Broadway last year (14), but King was initially reluctant to see her own life on stage.

She eventually attended a performance at the Stephen Sondheim Theatre in New York, but went alone and in disguise to avoid attracting any attention, and Mueller admits she was stunned when she spotted King in the crowd.

Mueller tells the New York Post, "(King was) in a disguise... And then, I think a little more than three-­quarters of the way through, she went to the lobby bathroom and changed back to Carole King and came back. I just couldn't believe it."