When you see a big name above the door of a stage musical, it pays to have a healthy scepticism about what they can bring to the table. Celebrities have their qualities – and the ability to pull in the box office bucks – but when it comes to holding their own on a stage filled with highly trained musical theatre performers, can they cut it? With Alexandra Burke, the answer is a resounding yes.

Sister Act has gone through various permutations, from the 1992 Whoopi Goldberg film, through the 2009 West End show to today's version, directed and choreographed by Strictly Come Dancing judge Craig Revel Horwood – who, it's fair to say, has given the production a real musical heart.

Everyone on stage earns their crust in more ways than one, so rather than hidden away in the pit, most of the musicians are characters on stage. It may take a moment to accept the police officer with a guitar slung round his shoulder, the gangster carrying a violin or lots and lots of nuns holding saxophones and trumpets – but once you do, the whole thing becomes a joyful celebration of music and song.

As sassy club singer in need of witness protection, Deloris Van Cartier, Burke proves herself to be a fine comic actor. Each witty line or facial expression is delivered to perfection – and when she opens her mouth to sing, we're reminded of why audiences voted for her in their millions during 2008's X Factor.

Karen Mann as Mother Superior also knows exactly how to bring home the laughs – which she does, on many occasions. She and Burke are at the heart of this warm, funny and entertaining production but they are by no means the only ones. Revel Horwood has done his job in every way, recruiting talented actor-musicians and then helping them shine through fun dance routines, vocal gymnastics, wit and charm.

Seen at Edinburgh Playhouse; Sister Act tours until Aug 2017.