Dev Patel was nervous about meeting Nicole Kidman.

The 26-year-old actor - who stars as Saroo Brierley in 'Lion' opposite the Australian actress as his adoptive mother - expected his co-star to be ''sweet and gracious'', though he was still in awe of her.

But Dev found it ''beautiful'' working with Nicole - who has adopted kids - Isabella, 23, and Connor, 21, with ex-husband Tom Cruise - and Faith, five, and Sunday, eight, with spouse Keith Urban - as she was just as committed to the movie as he was, especially because of her own family background.

He said: ''I knew she was going be very sweet and gracious -- she just gives off that energy. Once I got over the nerves of meeting Nicole Kidman. I saw how she really put in everything in the role.

''I'd been prepping for eight months, but she'd prepping for most of her life in a way because she is a mother with adopted kids.

''There was a real truth there. It was beautiful being in such an intimate performance space with her.''

For the film, Dev had to grow his hair longer and he admits his locks looked ''really awkward'' at some points, though he hasn't worried too much about what he looks like as he isn't bothered about ''grooming''.

He told Vulture: ''[My hair] went through some really, really awkward phases. I'm not really one for grooming, so I just let it grow wild. It's funny that it's gotten attention when really I just feel like I've got a mop on top of my head.''

Dev didn't meet the real Saroo until after he'd started filming, but they got along well as soon as they got together.

He said: ''The first scene I shot for the film was actually the climax, which was very difficult emotionally. Then we began the Australian portion of the film -- that's when I got to meet Saroo as that's where he still lives with his family.

''But it felt like I'd known him for almost a year, which is how much time I'd spent preparing; watching all the videos I could, absorbing all of his interviews and his talks. We immediately clicked over a really nice breakfast.''