Actor Dev Patel believes that working with director Garth Davis in his movie Lion helped him transform his physique from a 'celery stick' to a well-built man.

"I always felt like a goofy celery stick… I was a tiny twig, with short hair. Completely different to what Garth (Davis) changed me into," Patel, 26, told The Independent.

"Garth would say, 'We need to make you more alpha and get your facial hair growing.' So I moved differently, I felt differently in my clothes and all these kind of things."

Patel also opened up about some of the preparation he did for the role, including travelling around India.

"I went to India a month before I had to do my first shot and it was travelling the train and writing a diary of my feelings. I went to these orphanages and then you sit down afterwards and have to write down what you're feeling and that is when you digest it properly.

"I wrote a piece in my diary about the word hero, because you know the Bollywood stars when they are in public in India people call them hero, so they would call out hero to me, and I'm like, I wrote this thing in my diary about feeling less like a hero than ever before…," he said.

Lion is based on the true story of Saroo Brierley (Dev), a young Indian boy, who gets separated from his brother and mother when he ends up 1,000 miles away from his home, lost at a train station in Kolkata.