I can honestly say that I enjoyed all my lessons at secondary school, but drama was the reason I wanted to get up and go to school. In some lessons I could be a bit naughty and giggly - on more than one occasion my report said I distracted people because I talked too much - but I always concentrated really hard in drama.
Mr Sowerby was the head of drama. He was cool and sporty: he always wore jeans and trainers and was sort of like your friend, but I had too much respect for him to mess about. He was very tall and just took command of the room and he knew so much about drama.
He wrote these brilliant plays. I remember one in particular, called Saving Grace, which we put on at the Doncaster Dome. I played this naughty angel called Gracie, who had to earn her wings to get into heaven. I still remember it vividly. It was cleverly written and such fun to do.
I spent a lot of time with Mr Sowerby during my last couple of years when I worked for my GCSE in performing arts, but he taught me right through the school and was always a very big influence on me. I had only been at South Axholme School (near Doncaster) a short time when he told my parents they should take me to audition for the National Youth Music Theatre (NYMT).
The NYMT holds open auditions for children up and down the country. After we queued for what seemed like hours, I was seen and then I got a recall. Eventually, to my great excitement, I was offered a place and a small part in a show called Pendragon that was going to New York. It was only for a week, but it was amazing.
The great thing about the NYMT is that all the cast are kids, but you work with professional directors, choreographers and designers, so it's like a professional production. Of course we had to be chaperoned, but I remember waiting in the hotel lobby for the lift when who should walk out of it but my mum and dad. They said there was no way they were going to miss their daughter appearing on Broadway.
During that production, one of the leading girls cricked her neck just before she was about to go on stage and I was asked to go on in her place. I pulled myself together, tried to remember everything that Mr Sowerby had taught me and gave it my best shot. Anyway, it went really well and I was asked to go back another year to play Tallulah in Bugsy Malone.
I didn't realise I wouldn't be going back to school. I had done well in my GCSEs - I got an A* for performing arts - but an agent who saw me in Bugsy Malone took me on and then I got another job, in Stephen Sondheim's Into the Woods at (London's) Donmar Warehouse.
That was my first show with professional adults and my agent kept saying how amazing it was to be working there. I was so inexperienced that I didn't realise at first how prestigious it was. It's also a very small space so there were 12 of us sharing a dressing room - all these amazing actresses such as Sophie Thompson and Jenna Russell and Sheila Reid and then little old me. But they took me under their wing and then I got my first telly job, which was The Royle Family.
I'm very thankful, but I don't think any of this would have happened if Mr Sowerby hadn't encouraged me to audition for the NYMT. He brought some of his students to see Legally Blonde recently and it was quite emotional. I was really pleased because he said I hadn't changed, I was still the same down-to-earth girl he used to know.
He is leaving South Axholme at the end of the year, which is a shame but he has had an amazing run there; all the kids that have been taught by him have been so lucky. He is simply the best teacher - I owe it all to him.
Sheridan Smith is appearing in `Legally Blonde: The Musical' at the Savoy Theatre, London. See www.legallyblondethemusical.co.uk. She was talking to Hilary Whitney.