My best teacher was my form teacher, Mr Alun Guy, who also taught me music. When people ask me where my confidence came from as an actor, it was through music. I never got to play a lead in any of the school drama productions, but I had that opportunity to go on stage, singing solos and playing concertos on the oboe.

I played that instrument throughout my high school career. Sadly, it’s sitting gathering dust back home in Wales, though technically I could still pick it up and play it, no problem. I did my Grade 8, so I got to a pretty high standard.

Mr Guy was a man of the world. He was in his late forties, with a shock of curly grey hair and really cool glasses. He was always immaculately dressed and wore those silver cuffs that hold up your sleeves. He always poured on the aftershave Jazz, I think it was. He stood out from the rest because he was young in spirit. He used to train as a boxer, but he was also an amazing musician. He could have been a world-renowned conductor the next Sir Georg Solti.

He was also smart. He had studied the form of how the questions might go for your A-level paper, and he predicted what would be asked in the exam for a lot of the questions. When he was at university, he got hold of past papers for the music examination for his own degree. They studied Bach’s chorales and they had been asked to dissect them, and looking at the past papers he saw a pattern. So he only studied two specific chorales and they both came up. It was a four-hour exam and he was done in half an hour.

We studied Mendelssohn’s violin concerto for our A-level, though one of my greatest regrets is that I didn’t perform as well as I should have because I knew I was off to drama college. In the end, I got a C in music. When we completed our exams, Mr Guy treated us like adults, inviting us back to his house for a garden party. He gave us drinks and canapes in the garden. There was no doubt he was a classy guy.

He was the most encouraging of teachers we were constantly laughing in his classes and we were always singing in the choirs and playing in the school orchestra. He would take us on fantastic trips with the orchestra and we were given the chance to show what we could do.

Sadly, the last time I saw Alun Guy was at his wife’s funeral, but even then his spirit, energy and enthusiasm were still apparent

Ioan Gruffudd, 33, grew up in Wales and rose to prominence as the seafaring Hornblower in the eponymous ITV series. The son of two teachers, Ioan was born in a village near Aberdare, but did his GCSEs and A-levels at Ysgol Gyfun Gymraeg Glantaff in Cardiff. He has appeared in a variety of films, including Amazing Grace, King Arthur, Titanic and Black Hawk Down. He can currently be seen in Fantastic Four: Rise of the Silver Surfer. He was talking to James Mottram