LOS ANGELES, Nov 27 — Legendary US actor Robert Redford hit out at the Trump administration yesterday in a scathing open letter warning that America faced a "dictator-like” attack by a man who, he said, must be voted out of office in 2020.

"We're up against a crisis I never thought I'd see in my lifetime: A dictator-like attack by President Donald Trump on everything this country stands for,” the 83-year-old founder of the Sundance Film Festival wrote in an op-ed for NBC News.

"We have much to lose — it is a critical and unforgiving moment,” wrote the Hollywood heartthrob, who memorably starred in the 1976 political thriller All the President's Men about the Watergate scandal that brought down Richard Nixon.

"This monarchy in disguise has been so exhausting and chaotic, it's not in the least bit surprising so many citizens are disillusioned,” Redford wrote.

"It's time for Trump to go,” he said. "And it's up to us to make that happen, through the power of our votes."

Redford plays a fictional US president in HBO's new series Watchmen — which imagines a parallel world where the actor succeeded Nixon as head of state and remained in power for 26 years.

The screen legend had publicly praised Trump during the 2016 election campaign, saying he "shakes things up,” although a spokesman later clarified that Redford did not back the real estate mogul for president.

In his op-ed, Redford explained that while he did not vote for Trump, he had been willing to "give the guy a chance.”

But he said he was almost instantly disillusioned.

"There are only 11 months left before the presidential election; 11 months before we get our one real chance to right this ship and change the course of disaster that lies before us,” Redford wrote.

Fellow movie icon Robert De Niro has also been heavily critical of Trump, describing his presidency on Monday as "like living in an abusive household.”

"You don't know what's going to happen next, what crazy thing is going to happen next, what's going to make you say, 'what the hell is going on?'” the 76-year-old told The Late Show with Stephen Colbert while promoting his latest movie The Irishman. — AFP