SARAH FERGUSON, PRESENTER: In the world of surfing, the name Peter Drouyn is right up there in its roll call of stars. He was the Australian champion in 1970, and in the same year ranked number one in the world. Much more recently, he shocked his peers by undergoing a sex change and changing his name to Westerly. Now, a documentary team is hoping the story will change altitudes in this male-dominated sport and inspire others who are struggling with their identity. David Lewis reports.

DAVID LEWIS, REPORTER: In the 1960s and '70s, Peter Drouyn from Queensland's Gold Coast was at the top of his game.

MAL CHALMERS, SURFER AND FRIEND: He just had so much ability. I mean, he just put surfing on the map in Queensland.

TERRY 'TAPPA' TEECE, SURFING COMMENTATOR: Just, like, had that charisma, that certain je ne sais quoi, that thing that made people go, "Oh that guy," you know?

DAVID LEWIS: Described by his peers as eccentric, flamboyant and even arrogant, Peter Drouyn's good looks endeared him to both women and the cameras. The champion surfer even starred alongside supermodel Elle Macpherson in her first ever television commercial.

But behind the scenes, it was a different story.

So Westerly, what do you see when you watch Peter surfing?

WESTERLY WINDINA, FORMERLY PETER DROUYN: Oh, I see an incredible guy who's just amazing power.

DAVID LEWIS: Meet Westerly Windina, the woman Peter Drouyn always believed he was meant to be.

Although she shares his mind and to a lesser extent his body, Westerly Windina observes and speaks of Peter Drouyn as if they're entirely different people. And in a sense, they are.

MAL CHALMERS: Peter's been talked of in the third person for a fair while and I don't know whether it's been a cleansing process of all the hard times and problems that Peter had with life in general; that's why she's tried to expunge Peter from her existence.

DAVID LEWIS: The problems began for Peter Drouyn at a young age. He was convinced he was living inside the wrong body.

WESTERLY WINDINA: In those days, it was black or white. Hey, if you've got things between your legs, you're a boy, and if you haven't, you're a girl.

DAVID LEWIS: Uncomfortable around boys, he socialised with girls, but was happiest alone on the water.

WESTERLY WINDINA: That ended up being his therapy to stop him from going completely mad with this problem. It took him out into the ocean where he had this friend called his surfboard.

DAVID LEWIS: Peter Drouyn kept his struggles to himself, until his professional surfing career came to an end.

WESTERLY WINDINA: I suddenly started getting my own make-up. I was buying my own clothes. I was colouring my hair. I was doing it all secretly. I would go down the beach at midnight every night and dance and dance and if I saw a black shadow, I'd jump in the ocean and just submerge, you know, like a Rambo film or something.

DAVID LEWIS: It wasn't just a cosmetic change. In order to complete the transformation, Westerly Windina recently travelled to Thailand for gender reassignment surgery.

WESTERLY WINDINA: I could see that Peter was - Peter had passed away. Peter was - he's gone. ...

(Documentary footage): ... He did all sorts of things to try and tear the demon, the devil demon from his mind sort of a thing.

DAVID LEWIS: The extraordinary metamorphosis is now the subject of a documentary film, produced by the creator of the hit US drama series House of Cards. The project's director and writer, Jamie Brisick, has captured the surfing community's response to the departure of an icon and the arrival of Westerly Windina.

JAMIE BRISICK, DIRECTOR: I'm a product of the surf culture. I absolutely lover the surf culture. But the surf culture can be very, very narrow.

DAVID LEWIS: After some initial protestations, Westerly Windina agreed to appear at Surfing Australia's 50th Anniversary Dinner dressed as Marilyn Monroe.

WESTERLY WINDINA: People were yelling out, "Marilyn", and I'd turn around and I'd go, "Yes?" And, "Westerly", "Yes?", and they were all lining up like Stalin's funeral. Everybody wanted to talk to me.

DAVID LEWIS: But many surfers from Peter Drouyn's era kept their distance.

TERRY 'TAPPA' TEECE: Well amongst the surfing community, there was a bit of awkwardness. Some people that went, "Oh, wow, good on him," you know, like - or, "Good on her," you know, for actually coming out and doing it. Then there was others just going, "You're kidding, aren't ya?," you know, like, not such a good-looking woman. And, you know, there's been jokes everywhere and that, but, you know, like, it takes a lot of guts to actually do something like that.

JAMIE BRISICK: Most of Westerly's peers and contemporaries were I guess in denial. I mean, they just thought it was a performance. And Peter Drouyn had been such a performer.

MAL CHALMERS: There's a few people I know that still think it's a ruse, that it didn't really happen and that one day Peter'll jump out of a box and say, "I'm back," you know. But I can assure them that I'm confident that's never going to happen.

DAVID LEWIS: For now, Westerly Windina is feeling comfortable in her skin, expressing her femininity through song and dance, in the hope of becoming a performer.

JAMIE BRISICK: I only know Westerly; I never knew Peter, but I probably interviewed three or four dozen people who've known Peter for many, many years, and pretty much across the board they say that Westerly's a much happier person than Peter was.

DAVID LEWIS: Just like Peter Drouyn, Westerly Windina is on a mission to break boundaries.

WESTERLY WINDINA: If anything, they probably realise now why they never understood Peter and why they treated him the way they did.

SARAH FERGUSON: David Lewis reporting.