America's electoral system requires 538 electors to meet to confirm Trump's victory in November's (16) presidential election in a vote on Monday (19Dec16).

Electors usually vote for the candidate who won their state in the election, but they can technically choose any "eligible person" to be president.

In a video message the stars called on them to defy tradition and block Trump's accession to the Presidency as they believe he is unfit to lead America.

"Our founding fathers built the Electoral College to safeguard the American people from the dangers of a demagogue and to ensure that the presidency only goes to someone who is, to an eminent degree, endowed with the requisite qualifications," Sheen said, quoting America's Founding Fathers in the video.

Sheen, who famously played President Josiah Bartlet in White House based TV show The West Wing, called on the electors to protect Americans from "the dangers of a demagogue".

During a bitter campaign Trump was accused of racism and sexually assaulting multiple women, while the billionaire's business dealings also caused controversy.

Others who appear in the video include Better Call Saul actor Bob Odenkirk, ER star Noah Wyle, Babe actor James Cromwell, and the musician Moby.