© Phil Long (flickr)

If I worked for Equity, the actors' union, I'd be stamping my feet and throwing my toys out of the pram. In an industry where unemployment is a way of life, and more than 50 per cent of actors are living below the poverty line, according to a 2013 survey, how else do you greet the news that Freddie Flintoff has been cast in the new stage version of Kay Mellor's Fat Friends?

I have nothing against Andrew Flintoff. I watched him win the Ashes with England and I worshipped him. He played for Lancashire, my cricketing county. The affection engendered by his lively but lovely cricketing career has endured through his television appearances on shows such as A League of Their Own and Trollied. But he is a cricketer. Not an actor. And however amiable he ends up being on stage, it is an important distinction.

Casting celebs seems an insult to those who spend time learning their craft

Acting is a profession. You might think it is a spoilt and silly one, or you might - as I do - admire and like actors. But it is a profession whatever you think. As anyone who has ever tried to read a speech by Shakespeare, or even walk on a stage without falling over knows, it is not as simple as it appears. To try to do both at the same time requires skill. To do both at the same time and transport an audience by the power of your words and your presence, is an art.

So the modern trend for casting 'celebs' in leading roles seems to me an insult to all those poor souls out there who have bothered to spend some time learning their craft, and honing their abilities. If a genial ex-cricketer can rock up for a selection of dates on the tour and dazzle us with the benefit of his personality, why have they bothered?

Now you might argue that I am taking this news a bit seriously. Fat Friends is not Shakespeare. It is a jolly musical by Nicholas Lloyd Webber based on a popular TV series. Its lack of pretension has already been signalled by the fact that X Factor winner Sam Bailey (another person with minimal acting experience) has already been announced to star alongside Jodie Prenger (a woman who gained her acting experience only after coming to public attention through reality TV and Lloyd Webber père's search for a Nancy in Oliver!).

Sometimes the fame of the person interferes with the credibility of the part being played

But I increasingly feel that celebrity casting is selling the audience short. It is trumpeted as a way of getting people into the theatre, of giving them familiar and much-loved faces with whom they can identify. Yet sometimes the fame of the person interferes with the credibility of the part being played. I loved Annie and I am deeply fond of Miranda Hart. Yet there is no doubt that her essential niceness, which is the bedrock of her popularity, stood in the way of her portrayal of the evil orphanage boss Miss Hannigan, the Nurse Ratchet of musical theatre.

I found it even harder to watch Sheena Easton's high profile West End debut in 42nd Street. She was incredibly game, but watching her stagger through her dialogue scenes was like watching a high-wire walk undertaken by a toddler. Only when she sang did the warmth and strength of her personality emerge.

Yet both Hart and Easton do at least have a background in performance. They know how to sell a song. Flintoff? He knows how to heave a bat, bowl a cricket ball, sink a pint and tell a good joke. Even for a handful of performances, his appearance in a new musical is a farce.