The Republican leader unveiled his first budget proposal last week (ends17Mar17), unveiling plans to defund organisations like the National Endowment for the Arts (NEA), the National Endowment for the Humanities (NEH), and the Corporation for Public Broadcasting in order to increase spending on the military and homeland security.

Julie Andrews has already issued a plea to the President to reconsider the "mind-boggling" cuts, and now Redford has weighed in on the issue in a post on his Sundance Film Festival website, titled, "The NEA must survive - and thrive".

In the piece, Redford describes how his Sundance Institute, an organisation which supports independent filmmaking, and its annual movie event in Utah would never have been made possible had it not been for a grant from the NEA.

"That first promising investment from the NEA, and their belief in my project was vital to launching programs that now support tens of thousands of American artists working in film and theater and new media," he wrote.

"The NEA also very clearly helped us create the Sundance Film Festival, which turned into the leading international showcase for new voices and new artists to launch their work and find audiences for stories outside the mainstream," Redford continued. "No one has been more surprised than me at how far it's gone, and today the Festival brings millions of dollars of revenue to Utah over a 10-day period - proving that art can be an economic force."

He goes on to note, "Historic investment in the NEA has been fractional compared to other government spending but the dividends of this investment in our culture are unquantifiable."

As he concludes his open letter, Redford calls on readers to join the fight against the planned budget cuts.

"I believe the NEA must not only survive, but thrive," he declared. "Which is why I'm asking you to please join me in adding your voice to the chorus of concerned citizens by contacting your congressional representative and voicing your opposition to these cuts and in favor of continued support for the role the arts play in enriching our American story."

Redford's impassioned piece comes two months after he insisted Sundance Film Festival organisers would remain politically neutral, despite other stars voicing their disapproval of the then-President elect by leading protests during the January (17) event.