Out of all the books David Walliams has written, "The Boy In The Dress" is my favourite. However, some things work better on page than on screen.
The book had a lot great material that you can't cram into a one hour feature. Maybe in a two part mini series. That was the way it was done back in the good ol' 90's. And it worked perfectly.
There was so much of what made the book so great that didn't get into this feature. In the book we get to know more about Dennis coping with his parents' split, his love for dressing up in women's clothes and my fave character Mac, a boy who can't stop eating.
This feature had none of those and it just feels flat.
Also none of the jokes in this film were funny. All of the big names ad-lib and try their best but fail. Walliams himself has a cameo as a camp ref. Nothing that this character does is even the slightest bit funny.
The book is miles better and actually funnier too. Do yourself a favour and get a copy. Also get the audio book performed by Walliams and Matt Lucas. Their performances in that are better than the ones in this film.