Ex-Spice Girl Mel C joined the cast of School of Rock onstage for an impromptu performance.

After watching the show, the singer surprised the audience with a performance of "Wannabe", joined by the kids from the musical as well as David Fynn, who plays the lead role.

Andrew Lloyd Webber and Julian Fellowes' musical is an adaptation of the film starring Jack Black and won the WhatsOnStage Award for Best New Musical earlier this year. The show originally opened on Broadway before arriving in the West End last year.

The musical is directed by Laurence Connor and has lyrics by Glenn Slater, a book by Fellowes and music from Lloyd Webber. It tells the story of slacker Dewey Finn as he puts together his perfect rock band from a class of school kids.

School of Rock is booking at the New London Theatre until January 2018.