Timothy Spall, who has appeared in several previous Mike Leigh films, plays Turner.
The 57-year-old actor is a household name in the UK. To the rest of the world he is best known for playing Mr. Pettigrew in the "Harry Potter" films.
Spall, who was already a keen artist, took up two years of painting lessons to hone his craft for the role.
(sb1, Timothy Spall, Male English)
"When I did paint, start to paint, the frustrating thing was my teacher said 'you've got a sort of ability,' so every time I did something wrong it used to kill me. It wasn't as if I was an idiot and I didn't know what I was doing, I knew that what I was doing was either good or bad. So, it was a painful process but a great one because it taught me how to hold a brush, taught me how to look like I knew what I was doing, showed me how to mix the paint and all that."
His co-stars didn't spend quite as long researching their parts, but they did make some effort.
Marion Bailey plays a Margate landlady who becomes romantically involved with Turner.
(sb2, Marion Bailey, Female English)
"I did a lot of housework (laughs). I spent a lot of time in rehearsals sweeping up, scrubbing tables, washing windows, she bustles about. So that's what I did - making cups of tea for Mr. Booth, who Karl Johnson plays, and, yes."
Director Mike Leigh is famous for a filmmaking style that relies on improvisation-heavy rehearsals rather than a script.
It is an approach that is often elicited acclaimed performances, including Sally Hawkins in "Happy-Go-Lucky," Imelda Staunton in "Vera Drake" and David Thewlis in "Naked."
(sb3, Mike Leigh, Male English)
"Every single character you see in the film, including the smallest parts, I've gone through a process of developing a character and combining research with inventiveness to put on the screen these, what I hope are three dimensional real feeling people."
Marion Bailey has this to say about Leigh's directing style.
(sb4, Marion Bailey, Female English)
"He doesn't encourage you to talk about the work outside of it. It's just to do with the way he works. He's creating, initially, stuff on a one to one basis, he's evolving the character on a one to one basis. Then you get to work with other actors that your character is involved with, but generally you just don't talk about the job."
Dorothy Atkinson, who plays Turner's housekeeper, says a Mike Leigh 'biopic' is special.
(sb5, Dorothy Atkinson, Female English)
"It's more of a slice of life and nothing is heavy handed, it's just all subtle and everything is researched so well, in terms of period, the set, the costumes and everything."
("Mr. Turner" hits U.K. cinemas on October 31st and goes on to a limited release in the United States on December 19th.)