Blood Brothers, Phoenix Theatre, London

It can be a dangerous game parachuting a pop star into a much-loved musical – even when that musical is one of the West End's hardiest perennials and the popstar is Mel C, better known as Sporty Spice, or the Spice Girl who could sing. Willy Russell's Blood Brothers has been bringing audiences tearfully to their feet for 21 years in London and last night was no exception. Quite right, too. Melanie C (as she calls herself in the programme) is brilliant as Mrs Johnstone, the beating heart of the drama and a luminous stage presence even as her character grows ever more careworn and downtrodden.

And, boy, can she sing. It's a singer's role, after all: the former Spice Girl follows in the footsteps of such illustrious Mrs Js as Kiki Dee, Barbara Dickson, Carole King and Petula Clark. And while a little on the young side, the Liverpudlian is born for the part. She's lyrical and light on the recurring "Marilyn Monroe", sparky on "Bright New Day" and, finally, desperately impassioned on "Tell Me It's Not True".

Russell's musical – remarkably, he wrote the book, music and lyrics – has lost none of its dry-as-a-bone scouse wit, nor its terrible power to move as it reaches its quarter century. It's the story of the Johnstone twins, born into a single-parent family with too many mouths to feed. One is given away at birth to Mrs J's employer, the rich and brittle Mrs Lyons and grows up in a world of cricket, blazers and privilege, while the other flounders in petty crime and ends up on the dole. That they will always be drawn together, only to finally destroy one another is foretold, with a Gallagher-esque snarl, by Philip Stewart's sinister narrator who lurks on the sidelines in a devilishly sharp suit.

Stephen Palfreman and Richard Reynard are quite superb as the blood brothers, growing up in front of our eyes from seven-year old, catapult-wielding tykes to responsible young men. I loved and believed in every second of their tender interaction. Together with Mel C, they provide a wonderful introduction to the classic for first-timers, and for Blood Brothers fans, a good excuse to see it – and weep at it – once again.