Variety magazine reported this week that director Lee Daniels had tapped Fonda to play former first lady Nancy Reagan in an "all-star ensemble" being recruited for a film about a butler who served US presidents from 1952 to 1986.

Forest Whitaker is reportedly close to signing a deal to play the butler and talk show queen Oprah Winfrey is in talks to play his wife, Variety said.

Liam Neeson is being considered for the role of Vietnam-era president Lyndon Johnson, while John Cusak could play president Richard Nixon, it said.

Fonda, 74, was a staunch opponent of the Vietnam War, and in 1972 she visited Hanoi and was photographed sitting on a North Vietnamese anti-aircraft battery, sparking controversy and earning her the nickname "Hanoi Jane."

In recent years she has expressed regret over the incident, but many US conservatives still despise her, arguing she betrayed American troops.

Conversely, president Reagan, who served from 1980-1988, has come to be seen as a paragon of conservatism, with the 2012 Republican presidential candidates repeatedly invoking his name on the campaign trail.