Steven Spielberg says 'The Post' came together ''instantaneously''.

The 71-year-old director is a veteran of the movie business, and Spielberg has revealed that the drama film - which focuses on The Washington Post newspaper's attempts to publish the Pentagon Papers, a report into the US' military involvement in Vietnam - was the easiest film to make of his entire career.

He shared: ''There is only one category 'The Post' falls into, which is that it happened instantaneously.

''A lot of my movies take a long time to develop, I buy books, I do all the scripts, years go by, I make other movies instead. It percolates and comes back into my life and I finally get around to making them.

''In my entire span of 49 years professionally directing, I've never had a film come together this quickly.''

Spielberg also denied the suggestion that Donald Trump's shock win in the 2016 US election convinced him to make the movie, which stars Meryl Streep and Tom Hanks.

In fact, Spielberg claimed he was primarily motivated to tell the story of Katharine Graham, who led The Washington Post's coverage of the Watergate scandal.

He told The Hollywood News: ''I think the issues are much bigger than one administration. Had the election gone a different way, I would have still felt a real urge to tell this story.

''The first thing that attracted me to do 'The Post' was Katharine Graham, her story. Her evolution as a real person of real potential power that did not really have the facility to exercise that power because she hadn't quite found her centre of gravity, she hadn't been able to find how to use her own voice.''