Sir Ian McKellen is going back to his theatrical roots – in Coventry, he tells Roz Laws.

Sir Ian McKellen is wracking his brains, trying to remember how he felt when he stepped out on stage in his first professional role.

“Come on, it was 50 years ago!” he cries in a bid to excuse his memory lapse.

I venture that perhaps he felt nervous, as a fresh-faced 22-year-old in his first job at Coventry’s Belgrade Theatre.

“Oh no, I wasn’t nervous, I don’t think,” he muses. “I have never been nervous about an audience, I have always enjoyed acting so much.

“And I wasn’t aware at the time that it was such a big deal, that this was the first role of a career and where it all started. I hadn’t actually decided then to be an actor.”

In hindsight it was, however, a very big deal and one that Sir Ian – who is also in the West Midlands this week at Malvern Festival Theatre – is about to commemorate.

On Sunday, September 4 he is returning to the Belgrade to celebrate his career half century with a fund-raising event. He will chat about his life and craft and answer questions from the audience.

Sir Ian is especially pleased that it will be 50 years “to the minute!” since he played Roper in A Man For All Seasons.

After strutting his stuff on the Cambridge University stage with the likes of Derek Jacobi, Trevor Nunn and Margaret Drabble, he auditioned at several local repertory theatres.

He was offered jobs at Derby Playhouse and Hornchurch Theatre, but the Belgrade – then only three years old and the first civil theatre to be built after the war – offered him the highest salary, of £8 10 shillings a week.

Out of his wages, he paid £3 3 shillings to live in one of the theatre’s own flats.

“I had a wonderful time,” remembers Sir Ian, now 72. “I relished having such a wide range of roles, from Shakespeare and Agatha Christie to Chekhov, and working with some fantastic people like Leonard Rossiter.

“We used to drink after hours in the pub in the car park opposite.

“It was an exciting place to be. Coventry had taken such a battering in the war, but it was determined to get back on track. The new cathedral and precinct had just opened and there was a spirit in the air of ‘we are the future’.

“I haven’t been back at all since, so it will be nostalgic to return.”

But what of his very first role? His memory is still largely a blank about that.

“I asked our director, David Forder, about it. He remembers me wearing a pair of chef’s checked trousers on the first day of rehearsals, which he found alarming. So do I, I can’t recall having such an item in my wardrobe!

“He says I was bouncing up and down and was so enthusiastic. I don’t recall any of my lines in the play. It was enough for me that I had some lines, I was just thrilled about that.”

Sir Ian, of course, has gone on to have some truly iconic roles with plenty of memorable lines.

He was Gandalf in Lord of the Rings and Magneto in the X-Men films. He was Sir Leigh Teabing in The Da Vinci Code and Mel Hutchwright in Coronation Street. And on stage he’s been everyone from King Lear, Macbeth and Iago to Widow Twankey in panto. He even played himself in an episode of The Simpsons.

At the moment, Sir Ian is starring at Malvern Festival Theatre in The Syndicate, in what he describes as “a fantastic part, one of the best I’ve ever had”.

Running until Saturday, the play by Eduardo De Filippo sees Sir Ian play a Mafia Godfather in 1960s Naples. Antonio Barracano is a killer who rules the Naples underbelly with a rod of iron, providing a form of rough justice for the city’s criminals.

“I take on roles on the basis of ‘is it something I would like to see?’,” reveals Sir Ian. “And this part intrigued me. I was immediately attracted to it.