A year after announcing The Invaders, director (The Killing Fields, The Mission, City of Joy) Roland Joffe has cast Vivek Oberoi as Udaji, the film's hero.

Oberoi is the first Indian actor to sign the film. "I am very happy and thank God for being selected," he says.

The Invaders revolves around the Battle of Wadgaon fought between the British and the Marathas in 1779. The Marathas won that battle by burning fodder and poisoning wells in the village the British army would have to cross. As soon as the British reached Pune, the Marathas attacked and defeated them.

"The British had captured Mumbai, Chennai and Kolkata before this battle," says producer Ajey Jhankar. "To expand their territory, it was necessary for them to defeat the Marathas. They were unsuccessful until 1817 when they captured Pune."

"I was given an article on the Battle of Wadgaon to be translated from English to Marathi by a newspaper editor," he says. "I was impressed with the Maratha tactics against the British. I got so involved I decided I would make a film on this subject. Everybody talks about the Third Battle of Panipat in which the Afghans defeated the Marathas. Surprisingly, no one talks about this battle," says Jhankar. "I want more people to know about this historic battle."

"Udaji is the unsung hero in the Battle of Wadgaon," he adds. "This film is dedicated to him." Oberoi will play Udaji in Joffe's film. Asked if there would be a bigger role for Mahadji Shinde who led the Maratha army, Jhankar says, "There is a role for him, but our film is dedicated to this unsung soldier who won the battle braving all odds. The Marathas were 80,000 strong; the British 35,000. But the British were far superior in terms of arms and ammunition.  Ordinary Maratha soldiers stood by Mahadji Shinde and won the battle."

For Oberoi, meeting Joffe was an eye-opener. "I thought he [Joffe] would be some senior guy and I would have to go through a lot of protocol to meet him," he says. "When I rang the bell of his hotel room I was surprised. He came out to greet me, he was all alone. [He struck me as] so humble and approachable."

"Roland transported me to the great Maratha war," the actor says. "I felt like a Maratha when he was discussing the film with me. His narration was so good and so romantic. I am just four films old but Roland listened to me so patiently. He is so democratic."

For Oberoi, the reasons for choosing the film were simple: "I keep three things in mind while doing the film. First, the character and what his role in the film is. Second, the film. Third, the director's conviction. All these are there in the film [The Invaders]. I wanted to be part of it."

Oberoi plans to take six weeks off before he begins work on the film. Shooting will begin in September. It will also be shot in the United Kingdom and United States besides the Orchha-Datia-Gwalior belt in Madhya Pradesh, the Sahyadris in Maharashtra and some parts of Goa besides Mumbai's Film City.

Jhankar is confident his $40 million film will do well at the box-office. "Mel Gibson's Braveheart did well; so did Gladiator. Why can't this film succeed?" he asks.