The beefy singer took the place of the musical’s leading man Richard Fleeshman to perform the Unchained Melody sequence made famous by Patrick Swayze and Demi Moore in the classic 1990 film.

But, unlike Patrick, he disappointed fans by keeping his shirt on as he wrapped his arms around star Caissie Levy in the charity stunt.

Peter was asked to appear after the curtain call at the Piccadilly Theatre as part of the BBC’s Children in Need Pop Goes The Musical, a series of appearances of pop stars in West End shows.

He said: “I was so impressed when I went to see Ghost The Musical, it was one of the best shows I’ve ever seen. So when I was approached by BBC Children In Need to get involved, I jumped at the chance and just hope that I did it justice!

 “The cast were great and it was so much fun working with them and raising money for an amazing cause all at the same time.”

The Only way Is Essex stars Amy Childs and Harry Durbridge were on hand to watch the performance and were rewarded with a meet and greet with Pudsey Bear in the foyer.

Earlier this week Dionne Bromfield performed in Million Dollar Quartet and tonight The Sugababes are set to ‘pop up’ in smash hit Mamma Mia!

Tickets for ‘BBC Children in Need POP Goes the Musical 2011’ are available at http://www.bbc.co.uk/pudsey. Prices start from £25.