Colchester actor Scott Chambers is Sir Ian McKellen in new documentary

That’s Colchester actor Scott Chambers, who, two years ago, made his breakthrough with the part of Richard in the critically acclaimed Chicken.

Now the director of that film, Joe Stephenson, has cast Scott in the special documentary, which looks at the career of one of the most famous actors in the world.

Scott says: “The idea was to shoot some clips as flashbacks to his life. He knew nothing about it. I think he thought it was just an interview documentary kind of thing.

“At the time Joe and I were just talking about some other projects we could possibly work on and this came out of the blue.

“I play Ian McKellen when he first got into Cambridge and for it I had to learn this long Shakespeare speech which he had to learn to get in.

“If that wasn’t daunting enough, I was doing the scene with loads of people Ian knows in real life.”

As well as the Cambridge speech, Scott acts in a couple of other scenes when Sir Ian was performing for local amateur dramatic groups in Bolton.

All of which Sir Ian saw when the documentary was screened in front of a special invited audience in London.

“I was nervous as hell,” Scott jokes, “But Ian was so complimentary and I actually really enjoyed doing the Shakespeare in the end even though it was tricky finding the actual speech he did.”

Urged not to go into acting by his teachers, Scott Chambers has proved all the doubters wrong.

“The thing is,” he tells me, “a lot of my teachers at school and at college kept on saying to me I wasn’t good enough to be an actor. They were all very nice about it but basically that I wasn’t going to make it.

“Perhaps that’s what made me more determined.”

I suspect it was a bit of that and quite a bit of talent as well because you don’t make the shortlist for best breakthrough actor on determination alone.

Scott was one of 12 actors, including Downton Abbey’s Laura Carmichael, who were listed by BIFA, the British Independent Film Awards, as the most promising newcomers in 2015.

He got the nod for his breathtaking performance as Richard in Chicken.

Sir Ian turns 79 on Friday, May 25

“It’s just been absolutely crazy,” he adds. “I didn’t expect anything like the attention it’s got and when people talk about my performance in it I do feel really honoured if not a little weird.

“I remember I was shooting a horror film up in Glasgow and I was coming back on the train when someone told me the BBC’s Mark Kermode had reviewed the film.

"Someone had posted it online and I was trying to read it on the tube and it kept buffering, but when I finally saw it I couldn’t believe what he said. I was so pleased.”

Born and brought up in Colchester, Scott got the part of Richard, who has special needs, after being cast in the original play the film was based on at the Southwark Playhouse in London.

“It was like it was meant to be,” Scott jokes. “Up until then I had only done a few short films and I just wanted to do a bit of stage work.

“The director of the film, Joe, came along to see the play and liked the character I was playing. I think he really fell in love with Richard, saying that usually those kinds of characters don’t get a voice in cinema and he felt that Richard’s story needed to be told.”

Scott’s interest in acting started at an early age when his older brother showed him the classic slasher horror, Scream.

“I just remember him telling me, it’s not real, it’s not real, they’re all actors, it’s just a job,” Scott says, “and I thought to myself ‘that’s a job I want to do’.

“From then on I’ve tried to do acting whenever I could, even at school when I used to write scripts for my friends and class mates. They must have really hated me.”

Later while at Stanway School and then the Sixth Form College, he discovered Stagecoach performing arts school but could only stay there for a year because he was too old.

After getting a BTEC national diploma in acting from Colchester Institute, Scott then ignored the advice of his tutors and began going up to London to take ‘acting in front of the camera’ classes.

“Eventually I moved to London,” he adds, “and started doing adverts to pay the bills while I did short films for free on the side. But then the agent I was with went bust and I lost a lot of money. If it wasn’t for Chicken, I don’t know what I would be doing now.”

Thanks to Chicken and Playing the Part, Scott is busier than ever with another film due out at the end of June and a raft of other projects lined-up.

“I’m in a Disney film,” he tells me, “which is very exciting. It’s called Patrick and it stars Beattie Edmondson. I’m one of the students at her school and we filmed it last year.

“Then there’s another horror film, which i can’t say too much about, apart from the fact it comes out later this year, and then there’s a really quirky comedy called Mary and the Virgin. I play the virgin.

"I just loved that script, and finally I’m back working with Joe, which I can’t to do, on a suspense drama, but more on that later.”

• McKellen: Playing the Part, hosted by Graham Norton and broadcast live to cinemas nationwide from London’s BFI Southbank, takes place this Sunday, May 27, during Sir Ian’s birthday weekend.
• It runs at the Firstsite art gallery at 3pm. Tickets are £10.