Director Garth Davis said he put star Dev Patel "through hell" for his film "Lion" to ensure that the actor was prepared for the daunting role.

During an interview with Variety, the director discussed the film's journey to the big screen.

"I just wanted to see if Dev could do something that wasn't 'Marigold Hotel'," Davis said about the audition process.

"I put him through hell in his house in London, we had this acting workshop and he was just astonishing in that room." 

"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.

He gets adopted by an Australian family but eventually tracks down his lost family in India via Google maps years later.

The film also stars Oscar-winner Nicole Kidman, Rooney Mara and David Wenham.