The “celebrity lead” is often crucial to a show’s success, but in my experience it is unusual for an untrained celeb to really excel considering the vocal training and talent needed for a West End performer.

Mel C, who recently starred in Blood Brothers was one celebrity who did receive rave reviews and she brought new interest to the 21-year-old musical. Niki Evans, recent X-Factor semi-finalist now takes on the role.

But on the night I went to see Blood Brothers, Mrs Johnstone was played by Evans’ understudy Vivienne Carlyle. I didn’t realise this until the interval, but I never would have guessed had I not been told. Carlyle gave a charming rendition of this humble working-class single mum. Her voice is powerful with a beautiful tone and her acting is faultless.

The drama explores the subject of twins and the intriguing “nature versus nurture” debate. The brothers are played by Stephen Palfreman (Mickey) and Simon Willmont (Eddie), both tremendous. Palfreman convincingly portrays both the naughty schoolboy and the troubled adult, and is a pleasure to watch on stage.

Mrs Lyons was also played by the understudy, Rebekah Clifford. She is appropriately evil and a brilliant contrast to Carlyle.

Leaving the theatre, I felt quite overwhelmed (I cried for most of the second half). The understudies in this performance stole the show and made the night a triumph. Enjoy the understudy next time you see one, there’s a chance they’ll be better than the celebrity they are replacing.

Blood Brothers is on at the Phoenix Theatre until 31 July. Book tickets here