Bachchan will play Meyer Wolfsheim, a man with a dark past, who helps DiCaprio's character make money when he first comes to New York after the First World War.
"Bachchan, the elder statesman of Indian cinema and one of the most recognised faces on the planet, will play the role of Meyer Wolfsheim," Warner Bros said in a statement.
The 68-year-old star, who was in Sydney toward the end of August, where the film is being shot, did not disclose his reason for being in the city on his blog but did hint, saying, "Time has been spent well and hopefully judiciously. Days ahead will tell us whether it was fruitful or not."
The USD 125 million film is being adapted on the big screen in 3D by Baz Luhrmann, the man behind films like 'Moulin Rouge' and 'Australia'. The director has a fascination for Bollywood and even used hit item song 'Chhamma Chhamma' from 'China Gate' in the Nicole Kidman starrer.
Fitzgerald's novel begins soon after the First World War and depicts the "roaring 1920s" of America through the ill-fated love story of Jay Gatsby, who turns bootlegger to win the heart of his lady love, a superficial society woman married to a rich man.
While DiCaprio plays the title character, Carey Mulligan essays the role of Daisy Buchanan, his lover. Maguire plays Nick Carraway, the narrator of the story.