The King reigns in Hollywood

Struggling for words before pulling out a written text, Whitaker described his Oscar victory as a triumph over his humble beginnings in east Texas and the streets of south-central Los Angeles.

"When I was a kid, the only way I saw movies was from the backseat of my family's car at the drive-in. And it wasn't my reality to think I would be acting in movies. So receiving this honour tonight tells me that it's possible," he said.

"Through our combined belief, we can create a new reality," he added, thanking the people of Uganda for their spirit.

Whitaker prepared extensively for the part of the ruthless African strongman, learning Swahili and practicing Amin's accent after poring over books and hours of tapes and documentaries.

He also arranged meetings with Amin's brother and sister as well as ministers and generals who served in the Ugandan leader's government before he was ousted.

"I did more research for this role than any other character I've probably ever played," Whitaker said.

And the research paid off, helping him beat out Leonardo DiCaprio (Blood Diamond), Ryan Gosling (Half Nelson), Peter O'Toole (Venus) and Will Smith (The Pursuit of Happyness) to take home the best actor Oscar on Sunday.

Whitaker was born in Longview, Texas in July 1961 to a novelist father and a teacher who put herself through college to earn two master's degrees.

Now 45, he fell into acting almost by accident, when a promising career in American football was cut short by a serious back injury after he had won a scholarship to the California State Polytechnic University.

The sporting world's loss was the entertainment industry's gain, however, and after gaining admission to the University of Southern California to study opera, Whitaker later was admitted to the drama conservatory.

After graduating in 1982, he landed his first screen role in Fast Times at Ridgemont High, alongside future Oscar winners Sean Penn and Nicolas Cage.

Over the remainder of the decade, he became a familiar face in Hollywood, his acting talent, imposing frame and drooping left eye making him an instantly recognisable figure in a series of hit films.

Roles in The Color of Money and Platoon in 1986 were followed by his appearance as Robin Williams's earnest sidekick in the 1987 box office smash Good Morning Vietnam.

That was followed by a wonderful performance in the Clint Eastwood-directed Bird, the biopic about tortured jazz saxophonist Charlie Parker.

That performance won him the best actor award at the Cannes Film Festival and earned him a Golden Globe nomination.

Whitaker had less success during the 1990s, however. While there were memorable cameos - most notably as a soldier in Neil Jordan's IRA drama The Crying Game - there were few leading roles.

Much of that had to do with Whitaker's decision to move into work behind the camera rather than in front of it.

He co-produced and starred in 1991's A Rage in Harlem and was executive producer on the Emmy-winning television movie Door to Door.

Whitaker said he has discovered a new sense of self-assurance in recent years which persuaded him to take on bolder acting roles, including in The Last King of Scotland, and he believes the best is yet to come.

"I think that there's been an awakening inside of me, really honestly, and I honestly believe that the best work of my life is about to happen," he said.

"I'm finding a balance in myself as an artist from the external and the internal, and so as a result, the characters I play are going to be quite different," he said.