In the three years since he started acting, John Dartnell has appeared in a Harry Potter movie, dozens of television shows and a boy-band video.

Not bad for a 50-year-old musician whose look is more ZZ Top than Top Of The Pops.

With little in the way of thespian advice, John, 50, found his own path through the dog-eat-dog industry and is now carving out a successful career.

Having signed on with a respected agent, he has written a book with hints and contacts for anyone else hoping to work in the movies.

John, from Rodmell, near Lewes, said: "I've been a musician all my life but it now seems to be more and more about image.

"You have to have the right haircut and do the dance steps. Talent is secondary now.

"But in the acting world it doesn't matter how old you are or what you look like. You will be right for certain parts and it's the same as an extra."

John's most prominent role to date was as a teacher in hit film Harry Potter And The Chamber Of Secrets.

He said: "Since then I have been in a Robbie Williams commercial and appeared in the video for pop group Busted's song Year 3000.

"Until you get a name, it's difficult to get established but hopefully you keep moving in the right direction. If you've not had formal training, it's difficult even to be seen by an agent.

"You hear about people who charge £22, collect 10,000 people, and you never hear from them again. But everyone in this book is 100 per cent legitimate."

To order a copy of How To Get Into The Movies, go to www.makehits.co.uk/contentsmovies.htm