The show' Rock of Ages' is best known for its' vast array of tributes to the best of 1980's music, but at last night's stage performance in London the audience was treated to a classic from the 1970's.

Alice Cooper surprised the crowd when he joined the 'Rock of Ages' cast to belt out 'School's Out'.  Alice made the one-off appearance to mark the 40th anniversary of the song going to number one on the U.K. charts.