The London Film Festival celebrates its 50th anniversary this week with a gala screening of The Last King of Scotland to mark its 50th anniversary.
McAvoy (left) was given the Rising Star award at the 2006 Baftas
Actor James McAvoy talks to the BBC about his role in the film, which is set in Idi Amin's Uganda.
The film, an adaptation of Giles Foden's novel, centres on Uganda's dictator Idi Amin - played by Forest Whitaker - and explores an imagined relationship between him and his Scottish doctor, McAvoy's character Nicholas Garrigan.
The title refers to Amin's bizarre belief that he should be allowed to become king of Scotland - he was a fanatic about the country, and even took to wearing a kilt.
McAvoy told the BBC that he feels there is a dilemma facing Westerners who wish to make films about Africa, such as The Last King Of Scotland and last year's The Constant Gardener.
"We have to make films in Africa now, because we live in multi-racial societies," he said.
"To thoroughly examine our history and who we are, we must remember that we're multi-cultural, and so we have to look into the histories of other countries."
"However, if you're a white writer or white director, I don't think you can write the story of that African man. But if you are that Westerner, you have to write what you know, and the film is about the British presence in Africa at the time."
Rooted in reality
The actor, who won widespread acclaim for his performance as Mr Tumnus in last year's The Lion, The Witch And The Wardrobe, said he did not initially have much enthusiasm for the role of Dr Garrigan.
"What didn't appeal to me was that it was a story of a young white guy in Africa, and I didn't like that," he stated.
"However, then I realised he wasn't a hero - he's actually quite vain, arrogant and self-serving."
McAvoy explained that most of the film's plot is rooted in reality.
Although his character does not exist, he is a composite of three different real people.
"He gets to Africa and realises he's not having a great time, he's not having the African adventure that he thought he would have," he said.
"He bumps into the President, Idi Amin, and gets inducted into his life and becomes his official doctor, eventually becoming his unofficial right-hand man.
"By the time that he sees past his ego and his new empowerment, he realises that Amin has been killing hundreds and thousands of people and that he's actually a monster.
"Then, when he tries to get out, he can't get out."
McAvoy's co-star, Forest Whitaker, has already described how he became so immersed in playing Amin, he would dream like the dictator.
He has also said that it took him a long time to lose the Ugandan accent he acquired for the film.
The film premiered at the Toronto Film Festival
In contrast, McAvoy said that, when working on the film, he made a conscious effort to learn as little about Amin as possible.
"The director was very adamant he didn't want me to learn about Idi, he didn't want me to learn about Uganda," he said.
"He let me do research about my character, and who influenced him - but that was it. So he had me coming to it naive, very much like the character himself, so I didn't have any pre-conceived ideas.
"I knew he was a dictator, that he killed lots of people, and that he was by turns a clownish figure and a terrifying, horrific figure, but that's all I knew."