Lee selected Sharma from among 3,000 actors who auditioned for the part in the Fox 2000 film. Shooting on the fantasy adventure is to start early next year.
Life of Pi will be Lee's first 3D film. The script is by David Magee with Gill Netter producing. Fox will release on Dec. 14, 2012.
Pi tells the story of a boy lost at sea in shark-infested waters for 227 days in a lifeboat with four unusual and increasingly hungry companions -- a Bengal tiger, a hyena, a zebra and an orangutan.
Per Variety, the novel, winner of the Man Booker Prize, was a global publishing phenomenon when Fox 2000's Elizabeth Gabler acquired rights. At that point, M. Night Shyamalan was attached to direct, but he exited early on because of scheduling conflicts.
Though Lee and Fox execs did not disclose the budget, Lee told USA Today he asked for more than $50 million. "It's expensive to shoot in 3-D," Lee told the paper. "I know it's a great burden on me, but the story kept haunting me, and 3-D was the way for me to crack the book."