Sir Alec Guinness is portrayed as an elusive figure in the documentary
Sir Alec Guinness was one of the 20th Century's most respected actors.
But as a man he remained an enigma throughout his life - even to many of those who knew him.
A feature-length Arena documentary Sir Alec Guinness: A Secret Man, attempts to uncover the complex and elusive figure behind the many screen roles.
Featuring interviews with friends, family and those who worked closely with Guinness, it reveals a troubled figure who sometimes appeared to be acting out roles even in his own life.
Director-producer David Thompson, who made the film over the course of six months, said Guinness proved to be an intriguing subject for an in-depth documentary.
"No-one had really made a detailed film about him before," he said, "and the opportunity arose to tie in the documentary with a new official biography written by Piers Paul Read - one of the contributors to the programme."
However, Thompson says Guinness' secretive personality also made the project a challenging one.
"He was a very private person - a very difficult person to get to know," said Thompson. "He didn't like to confess his true feelings to people, and even those who were quite close felt there were barriers."
The film paints a portrait of a man who struggled to come to terms with his bisexuality. It also concentrates on his conversion to Catholicism in the mid-1950s and his reputation for emotional coldness - even with members of his own family.
"He could certainly be dismissive of Merula, his wife," says Thompson, "but I hope that the film is not imbalanced in its portrayal of him.
"He could also be a very generous and funny man - and I hope this comes across as well."
Alec Guinness - Key films
Great Expectations (1946)
Oliver Twist (1948)
Kind Hearts And Coronets (1949)
The Lavender Hill Mob (1951)
The Ladykillers (1955)
The Prisoner (1955)
The Bridge On The River Kwai (1957)
Tunes Of Glory (1960)
Star Wars (1977)
One of the tasks in making the film was selecting which roles to highlight from Guinness' long and versatile career.
He was acclaimed as both stage and screen actor (director Ronald Neame describes him as "perfection in both mediums") and could switch with apparent ease from comedy to serious roles.
"In the film we tried to pick out the roles that reflected the man," said Thompson. "There was a feeling that some roles did come quite close to him.
"There was a playfulness there, a seriousness and also a volcanic quality - something which he showed in Tunes Of Glory, for instance."
Guinness' Oscar winning performance as the disciplinarian Colonel Nicholson in The Bridge On The River Kwai is featured, together with his comic tour-de-force as eight members of the same family in the Ealing classic Kind Hearts And Coronets.
Thompson also chose to focus on his one of his lesser known roles, as a cardinal in the 1955 film The Prisoner. He describes the performance as Guinness "at his rawest", and adds that the actor converted to Catholicism the following year.
Spymaster George Smiley was one of Sir Alec's defining roles
Yet the role of spymaster George Smiley in the BBC TV dramas Tinker, Tailor, Soldier, Spy and Smiley's People that is regarded by many as being closest to Guinness himself.
"It was his last major role," said Thompson, "and an extraordinarily minimal and moving performance."
Contributors to the film range from novelist and Smiley creator John Le Carre to actress Dame Eileen Atkins and film director Ronald Neame. And they are unusually candid in their assessments of Guinness.
"I was rather surprised by the honesty of some of the interviewees," said Thompson, "and pleased with their contributions.
"I think it reflects the quality of people that Guinness sought out. He enjoyed intelligent company."
While the film sheds some light on Sir Alec's personality, Thompson concedes that he remains an elusive figure.
"There are still a lot of questions to be answered, but I'm not sure that anyone will be able to find out more about him - simply because that was the nature of the man," he said.
"Even his own son felt that in many ways he didn't know him."
And what is Thompson's own assessment of Sir Alec's character?
"If I was asked whether I would like to have met him, I think the answer would probably be no," he says.
"If someone was an actor, or if they had a particular musical or literary gift that he admired, then he would take an interest in them. But beyond that I don't think he was very interested in people."
Sir Alec Guinness: A Secret Man is screened on BBC Two on 29 December at 2100 GMT.