The actor, whose father was Indian, has fond memories of the man and was glad he'd studied his movements and ways from the back seat of his Ambassador car - because it made his research for the new Isabel Coixet film easy.

He tells WENN, "I have an extraordinary memory and I can bring something back when I need it. When I was filming Gandhi, every day I was greeted by my Sikh bodyguard driver. Every day I drove to the set looking at the back of his head, his turban, how he'd gently move from side to side whenever I asked him a question. How he would have really voraciously defended me had anything happened.

"I think one of the indelible images I have of him was him looking at me in his rear view mirror and I was sitting in the back of his Ambassador car, which is the classic Indian vehicle. It hasn't changed in 40 years. He was driving me away from the largest crowd you've ever seen on the screen in the cinema - the funeral procession.

"It was a traumatic day for me because I was on the funeral wagon, hardly breathing, for nine hours! When I got to the other end of the wonderful road down which Gandhi was born as a dead saint, I had to ask my first AD (assistant director), dressed in a British uniform - because they were extras in the film, 'Steve, how many people are here?' He said, 'About 40,000, sir'. 'How am I going to stand up in front of 40,000 people; I've been dead for nine hours?' I was quite stiff.

"He said, 'I'll help you'. He lifted me up and I saw 40,000 people go very quiet, because I had just broken the spell and come back to life... One by one, they started to clap and they all started to sing. And the women who had a blue stripe at the edge of their sari lifted me off the back of the truck and carried me to my driver's car. He was standing at attention waiting for me!

"I fell into the back seat and he got into the driver's seat and we had to move through 40,000 people to get back onto the main road to go home. He looked in the mirror and said, 'Well done, sir'. I treasured this moment, and now I'm playing him! I used his stillness, his strength, his kindness and his economy of words. Sikhs are very unsentimental people but very emotionally developed. Amazing."