Hollywood star Sophie Okonedo discusses her role as Winnie Mandela in new one-off BBC4 drama Mrs Mandela. It follows Nelson Mandela’s ex-wife’s transition from poor country girl to disgraced revolutionary and accusations of murder.

She’s a very controversial figure, did that affect how you approached the role?
“I approached playing Winnie the way I approached playing any other role, which is to try to get to the heart of it and play the truth as much as possible. It’s not very useful to me to make moral or political judgements about the characters I play because it would separate me from the character. It’s almost easier to look at the script and imagine a fictional character to begin with and put my personal beliefs aside.”

How much research did you do?
“I didn’t watch much footage of her because I didn’t find it useful. I’m not an impersonator and watching the footage made me feel separated from her. I got familiar with the facts of South African history and read a lot of books.”

Was it an intense shoot?
“It was a low budget film so we were running around getting changed in the backs of cars! You’d do a scene and then in the next one you’d be playing someone who was 30 years older. It was constant excitement and I was constantly thinking ‘I’m so lucky to be doing this’.”

Did you find it difficult to film the scenes of torture and interrogation?
“I tend to have a laugh and distract myself between takes so I’ve got more energy when they say action. I was on high for the whole shoot and found it all so exciting and interesting, including the dark and difficult scenes because they are part of a wonderful script.”

Did you find it difficult to do the accent?
“I had a very good dialect coach who made it very easy for me. I have to confess I didn’t do any work on the accent till I got there but then I worked really hard.”

What was it like filming in South Africa?
“I love it there. We were in Soweto filming in real locations – round the corner from their real house, walking the same streets she walked, which made everything so much easier. I was never bored and just loved every single minute of it.”

What was the reception like from local people?
“It was really good. People were so positive. And I was so nervous! One of my first scenes was of her famous speech in a big hall in front of loads of people. I felt like a complete fraud and all I could think was ‘How am I supposed to go up there and be one of Africa’s most iconic women?’ But all the big scenes were great because the extras in South Arfica are superb.”

What do you think was the initial attraction between Winnie and Nelson when they were younger?
“At that time he was very well known as an up-and-coming mover and shaker but she really was quite a country girl. I don’t think there’s any surprise about her attraction to him – I’d say a lot of women were attracted to him at that time. And I think he was attracted to her because she’s an exciting and fiery person. She was incredibly beautiful when she was young. People we talked to who knew her said that she used to light up a room she was so charismatic.”

How did you find the physical change and numerous costumes?
“I’d more costume fittings on this than I’ve ever had on anything. Winnie loved her clothes so I got really into it. I even loved the fat suits! Although it was really hot while filming I just imagined I was in a stream room detoxing!”

What do you think will surprise people most about this film?
“I think the power of this drama is it doesn’t portray anything in black and white as life isn’t like that. I don’t think Winnie Mandela suddenly became the person we know today. In the grey areas it is possible to feel and think different emotions at the same time, and I think the film does that. It’s the power of drama.”

Mrs Mandela is on BBC Four at 9.00pm on Monday January 25.