Hot off his New York Film Critics Circle win for best actor, Timothy Spall steered the topic of conversation more toward his painting skills than his acting chops at the Variety Screening Series on Wednesday night.

Spall depicts British landscape painter J.M.W. Turner in director Mike Leigh’s biographical drama “Mr. Turner.” Leigh had mentioned the idea for the film to Spall five years before the thesp expressed interest in the role.

Spall said he was “walking around London aimlessly, trying to be enigmatic and failing” when he found himself outside a pub in Covent Garden, sitting under a sign that read “J.M.W. Turner was born here in 1775,” in a moment of serendipity.

He called Leigh, with whom he collaborated on 1999’s “Topsy-Turvy,” to inquire about the Turner project — and the director just so happened to be in the process of developing it.

“He said ‘Well, don’t get excited ‘cause it’s not 2010, it’s going to be called ‘Untitled 2013’ ’cause they always are. We haven’t got the money. It’s going to be about Turner.’” Spall recalled. “I said, ‘I presume that’s J.M.W., not Tina.’ He said, ‘Not only that, would you do me the favor of going to learn how to paint for a couple of years?’”

So Spall took painting lessons for two years, in addition to the six months of preparation and rehearsal involved before shooting.

“When I was being taught how to paint it became apparent, much to my surprise, that I had a certain amount of ability, which was good for the teacher, but bad for me,” Spall told the audience at ArcLight Hollywood following the screening of the pic. “Because every time I painted, I knew when I was crap, so a lot of the painting lessons became an exercise in self-hate because I knew I just wasn’t ever going to be anywhere near as good as he was.”

The research process didn’t stop there, as Spall had to read biographies and examine Turner’s works in order to be knowledgeable enough to improvise. As is customary for the writer-director, Leigh built the film scene by scene as the actors improvised without a script, often for three or four hours straight.

“All the time you’re building an organic human like a sort of actorly Frankensteinian…” he said. “And then what you’re trying to do is reach it towards and bring the research towards the man and then smash it up together and mix it up so hopefully in the end it becomes indivisible and you got this piece of humanity that’s existing in a world that you’ve also created and that you’re delving into when you’re improvising.”

His decision to grunt and growl (he said “critics have chosen every animal from the menagerie of the zoo” to describe the vocalization) his way through the majority of the movie was also partly his invention.

“It grew organically,” he noted about his proclivity for incoherent noises. “There were many eyewitness reports about how (Turner) had a very deep and a very uncultivated strong London accent — Cockney being the nickname for it. A lot of people often couldn’t understand what he was saying. He was at times very non-communicative.”

When he wasn’t channeling his simian ancestors to comic effect (which he wasn’t fully aware of doing until he heard his crew grunting at each other), he was speaking in Georgian English.

“I was seriously ill and I had a long period of recovery,” Spall said, recalling an earlier time in his life. “As a way of escaping what might or might not happen to me because there was a sort of question mark about it, I read all of Dickens back to back so I had this very strong, distinctive and passionate feeling for late Georgian, early 19th century English and Mike knew that.”

When asked by an audience member whether he was scared of taking the character too far over the top, Spall said he was, but ultimately relinquished control of the character to the character itself.

“I don’t want to sound mystical about it, or bonkers,” he prefaced. “The character itself starts to dictate to you so your fears about it being over the top or too extraordinary are secondary to the fact that it’s telling you what to do. It’s a bit scary, but it’s seemingly the only way you can go.”