Nicole Kidman feared she would "let down" the adoptive mother whom her 'Lion' character was based on.
The 49-year-old actress - who has more than 30 years experience in the film industry - felt the pressure to get things right on the set of the Oscar-nominated movie.
When asked whether she felt cautious over meeting the adoptive mother Sue Brierley, she told Total Film magazine: "It was more like I didn't want to let her down. Obviously, it's a supporting role, so it's not her story - and she contributes to it. But her story itself - her life story - is so compelling."
The film is based on a five-year-old Indian boy Saroo, played by Sunny Pawar and Dev Patel, who gets lost on the streets of Calcutta, thousands of miles from home. He is eventually adopted by a couple in Australia and 25 years later, he sets on a mission to find his lost family.
Kidman admitted she was worried she wouldn't be able to do Sue's story justice and "honour" her life.
She added: "I was like, 'Gosh, I hope I can somehow get her essence into the amount of screen time I have so you can really feel who she is and what she is.' So I wasn't reticent to meet her, but I didn't want her to feel that everything she shared with me - because I spent so much time with her - was not on the screen, because it couldn't be. But I wanted to somehow honour her life."
And Kidman says that when she first read the script, she wasn't aware that it was based on a real-life story but still found it hugely emotional to play.
She shared: "But then when I found it was a true story, I was like 'Oh...' but subsequently getting meshed in the whole world of the Brierleys and getting to know Sue and the whole family .... they're pretty special but she's just had very, very unusual life, and at times traumatic life, and yet she managed to pull it all together and give these boys this beautiful future and life. And that's the thing that touches me the most."