Charlize went through a remarkable transformation for the film

She was nominated for her role as a serial killer and prostitute in the film Monster.

She is South Africa's first ever Oscar winner and President Thabo Mbeki led the congratulations.

"Theron has proved that we as a nation can produce the best in the world," he said in a statement.

Holding back tears as she accepted the award, Theron said she would be taking her Oscar statuette back home country next week.

Correspondents say the former model and ballerina, 28, underwent a remarkable physical transformation to play her role, adding an extra 13.6kg.

'Too upmarket'

However, residents of Theron's home town of Benoni, near Johannesburg, were upset when Monster did not open as scheduled on Friday, reports the AFP news agency.

Theron played a serial killer

A spokesperson for Monster's local distributor Nu Metro had said the film was too "upmarket" for Benoni.

"It caters for a particular niche. The people of Benoni... want to see Charlize in movies like Italian Job, not Monster."

Local butcher Tienie de Beer, who remembers Theron buying meat from her shop as a child, voiced local anger:

"Why do they do this to us? We must support her. She's such a good actress," she said.