SHE is not be as famous as JK Rowling, but mention Jacqueline Wilson to any girl under 16 and she'll be able to tell you her favourite book by the writer.

Her fiction, aimed at eight to 14-year-olds, crosses boundaries and strikes chords in young readers with its world of awkward adolescents and bizarre parents.

And her best known book, Double Act, a story of identical twins Ruby and Garnet forced to move to the country with their dad and his new girlfriend, will be coming to the New Theatre from Monday.

This new adaptation by Vicky Ireland has even gathered praise from Wilson herself, who said: "Double Act is my favourite of all my books - I'm thrilled that it has been adapted!

"I am an only child and like many other only children I was fascinated with the idea of having a sister, or even more wonderful, a twin; someone who could be your best friend, someone who you could play with and with whom you would always have something in common.

"If I was going to write about twins I wanted to write about what happened to them in a state of crisis. Something that meant they couldn't get on with their ordinary lives, therefore making it more important than ever to develop special twin tricks that hold them together.

"I developed the idea of a lost mother as it was dramatic enough to make the twins heavily dependent on each other, a situation that they must break out of as they grow up.

"It's fun to write about naughty children and what they get up to! Ruby is always going to be a mischievous girl, she is outrageous, yet I hope that the children watching will understand why she acts up and realize that she has had a tough time."

Double Act is at the New Theatre, Cardiff, from Tuesday to Saturday. Tickets cost from £6 and the show begins at 7pm every evening with 2.30pm matinees on Wednesday, Thursday and Saturday. Box office 02920 878889.