The American Honey actor launched the four-year project, titled HE WILL NOT DIVIDE US, with 18-year-old actor and rapper Jaden Smith on Friday (19Jan17).

Shia and Jaden asked members of the public to protest against the newly installed U.S. leader, Donald Trump, for the duration of his presidency by chanting "He will not divide us" in front of a camera fixed outside New York City's Museum of the Moving Image which will be live streamed.

However, in footage live streamed on Sunday (22Jan17) a man positioned himself in front of the camera and shouted "We must ensure the existence of the white people as a race," enraging the 30-year-old star, who was standing nearby.

Shia responded by angrily confronting the man, screaming his "He will not divide us" slogan in the interloper's face repeatedly and barging him away from the camera.

The phrase that caused Shia to react angrily is similar to an infamous white supremacist slogan known as the Fourteen Words.

The altercation between the actor and the white nationalist came towards the end of a weekend of protest greeting Friday's (19January17) presidential inauguration of Trump, who has received political support from white supremacist leaders.

Millions of women around the world marched to protest Trump's succession to the U.S. presidency, with a main march in Washington D.C. drawing support from celebrities including Katy Perry, Madonna, Scarlett Johansson and America Ferrera.

The march was the scene of another altercation between an anti-Trump protester and a nationalist, as Richard Spencer, a leading white supremacist, was punched by a passer-by while giving a TV interview.