Portrait of Australian actor Ewen Leslie.

Hidden depths ... Ewen Leslie's intensity is leavened by a light-hearted demeanour. Photo: James Brickwood

Ewen Leslie barrels out of Belvoir St Theatre's rehearsal rooms looking every inch the brooding, intense thespian. He paces, cigarette in one hand, plastic bag with his lunch in another. He mutters to himself, oblivious to the stares of passers-by who must be wondering about the meaning of the words: ''She wore a tall bearskin cap. A shako they call it.''

When Leslie looks up to take a long draught from his cigarette, his mood suddenly changes as he snaps out of playing Brick, the emotionally constipated son of an ailing southern-American patriarch in Cat on a Hot Tin Roof.

It's the midpoint of rehearsals for Belvoir's production of Tennessee Williams's classic 1950s play, and Leslie is still coming to grips with a script he says ''you sort of have to treat like it's Shakespeare''.

He says the playwright was a perfectionist who would tear up a page if he believed one word was out of place, which adds pressure, perhaps, to playing Brick.

''He's somebody that for pages and pages doesn't speak,'' Leslie says. ''I mean the opening scene with Maggie is about 33 pages and I have maybe nine or 10 lines.

''It's mainly her speaking, trying to prod me and get something out of me. I haven't really played someone like that before and it seemed incredibly challenging and kind of scared me a bit.''

Bold acting choices have been a hallmark of Leslie's career since he played the garrulous Prince Hal in The War of the Roses, an eight-hour epic directed by Benedict Andrews for the Sydney Theatre Company in 2009, during which he delivered a 20-minute monologue.

Andrews says Leslie combines raw honesty with a fierce intelligence.

''Watching him act, you have a sense of hidden depths, that there are unseen layers beneath his performance,'' he says. ''These qualities made Ewey a perfect fit for Hal.''

That performance won Leslie a Helpmann Award and the best supporting actor gong at the Sydney Theatre Awards in 2009.

The following year, he collected more trophies for the title role in the Melbourne Theatre Company's production of Richard III, before picking up a 2011 Sydney Theatre Awards' best-actor nomination for playing the wound-up, vulnerable Hjalmar in The Wild Duck.

Last year, Leslie appeared on the small screen in Mabo and Devil's Dust and the film Dead Europe, based on a Christos Tsiolkas novel. His previous films include Sleeping Beauty and the short Jewboy.

The 32-year-old even dabbles in video art, appearing in artist Oliver Watts's The Sea Hare, a retelling of the Grimm fairytale, which is on exhibition at Chalk Horse gallery in Surry Hills. Asked why, Leslie's response is: why not?

''My initial reaction is I've never done anything like that before so I'm sort of open to the experience,'' he says.

It's an impressive track record for someone who nearly got thrown out of a specialist performing-arts high school for skipping rehearsals.

The oldest of three children, Leslie was born in Fremantle in 1980. He does not come from a family of actors. His father, Norman, is a retired photography lecturer; his mother, Susan, works for a mining company.

He scored his first acting job at the age of 12 after his mother saw a newspaper ad calling for boys to audition for the children's television show Ship to Shore.

Leslie says the show was a ''wonderful thing to do'', even if it was boring at times. After shooting finished, he found it difficult to return to the routine of high school.

''It was a really difficult transition and I was a brat, really,'' he says. ''I started wagging a lot of school. I drove my parents crazy.''

Leslie was about to lose his high school acting scholarship when he was cast in David Williamson's The Removalists.

''It was the first time I'd ever done theatre and had an audience and experienced the immediacy of that and I just completely fell in love with it,'' he says.

Leslie talked his way back into school thanks, he says, to the often-maligned Australian playwright: ''I owe David Williamson a lot.''

After earning an acting degree from the Western Australian Academy of Performing Arts, he found himself in Sydney working behind the bar at the Old Fitz in Woolloomooloo. He lived in ''rough digs'' above a leather shop in Surry Hills for five years with fellow actors and West Australians Toby Schmitz and Travis Cotton.

Leslie's early roles were in comedies performed in the theatre below the hotel where he met his partner, film producer Nicole O'Donohue. Schmitz says: ''He threw himself into independent theatre when no one wanted to employ him, and now they do he is still addicted to the stage, which is the greatest quality in an actor in my eyes.''

Schmitz is glowing in his assessment of his former flatmate, with whom he shared the Belvoir stage in The Wild Duck, seeing the upside of even potentially negative traits.

''He is a grand worrier; he stresses over many things I simply ignore and he stresses wildly about them,'' Schmitz says. ''A notorious insomniac, sometimes you'd hear him at night pacing.

''Things I should be worrying about eventually worry Ewey until he has to have a quiet word with me about them, and he's always spot on. I should be worried.''

Leslie says he was attracted to Brick, a closeted former footballer drinking his way through an unhappy marriage in Cat on a Hot Tin Roof, because he seemed the polar opposite of many of his roles in recent years.

''I've tended to play a lot of characters who are very much on the front foot, in people's faces, proactive and doing a lot on stage to get stuff out of people,'' he says. ''Brick … seemed very different from that.''

Leslie is wise to be cautious in his approach to Brick, who was famously played by Paul Newman in the 1958 Oscar-winning film alongside Elizabeth Taylor.

Williams's Pulitzer Prize-winning play rakes over the deceits of a fractious family gathered to celebrate the birthday of their patriarch, Big Daddy Pollitt, who does not know he is dying of cancer.

Big Daddy's true diagnosis and many other secrets are revealed during the course of one evening, including Brick's sexless marriage to Maggie the Cat, his drinking problem and the true nature of his friendship with Skipper, who killed himself after telling Brick he was attracted to him.

Leslie immersed himself in the world inhabited by the Pollitt family by reading books and watching films set in Mississippi, but his ultimate goal is to decipher Brick.

''When you're researching a role, you're trying to do everything you can to try and get to the bottom of someone,'' he says, ''and possibly find places in your own life or experiences you can use to fill that out. It's funny with Brick because he's so ambiguous … there's so much about him that's left unanswered.''

The biggest question mark relates to Brick's sexuality and whether his relationship with Skipper went beyond the ordinary bounds of 1950s friendship in the American deep south. Leslie says his character comes incredibly close to telling his ailing father that he is gay: ''It's all about to be said and then he makes a quick right turn and fires all his bullets at Big Daddy.

''I don't feel a whole lot of responsibility to clear up that ambiguity … because I think Tennessee Williams deliberately left it that way.''

But it was too much for US movie censors in the 1950s, who demanded changes to Williams's script, removing the homosexual themes and including a scene in which father and son reconcile. However, a 1974 stage production directed by Elia Kazan restored much of Williams's original text.

Belvoir's production of Cat on a Hot Tin Roof, which opens a month after a Broadway revival featuring Scarlett Johansson as Maggie, is directed by Simon Stone.

Stone's previous attempt at a classic 20th-century American play, Death of a Salesman, became mired in controversy when he changed the way the protagonist died. This time the director says he has made only one change to Williams's script, replacing the word ''rut'' with ''f---'', although he has not asked the cast to perform with southern accents.

Cat on a Hot Tin Roof is the third Stone-directed Belvoir play that Leslie has appeared in following 2009's The Promise and The Wild Duck in 2011. ''I'm always looking for roles for Ewen to play,'' Stone says. ''He's capable of pretty much anything within reason and I like to find new territory we can discover together.''

The pair first met on the set of the 2006 film Kokoda. Later, after seeing Leslie play a young Orthodox Jew in the 2005 short Jewboy, Stone told him he hoped to direct him one day.

''At the time, I was still an actor. I hadn't directed anything before so it was a weird thing for me to say,'' he says. ''I get actor crushes all the time. The relationship that has resulted out of this particular actor crush is one of the most satisfying.''

Stone says Leslie can be intense when trying to unravel a character, especially if he feels he has to work harder in the rehearsal room.

''But as a friend and a person in the world, he is incredibly light-hearted,'' Stone says. ''He has to be to counteract the depths to which you sink into your own psyche when you're working.''

Cat on a Hot Tin Roof begins previews on Saturday at Belvoir St Theatre.