Oscar-winning actress Kate Winslet is "game" for anything, even being dunked in freezing water while pregnant, Alan Rickman has revealed.

The Sense And Sensibility co-stars reunited for period drama A Little Chaos, which the Harry Potter star directed, after almost 20 years since their last movie together.

It was a chilly reception for Winslet, who found herself thrown into ice cold water for a night scene, despite being pregnant with her third child Bear at the time.

"Unfortunately that was in the script. So it was a nervous night, I can tell you," Rickman said at the film's premiere at the BFI London Film Festival.

The 68-year-old, who also stars as King Louis XIV, continued: "It was about one o'clock in the morning and she was about 14 weeks' (pregnant) at the time. But she's game for everything. That woman is a pro."

Winslet stars as strong-willed landscape gardener Sabine De Barra, who challenges sexual and class barriers when she is chosen to build one of the main gardens at King Louis XIV's new palace at Versailles.

The film also stars Belgian heartthrob Matthias Schoenaerts as her love interest, as well as Stanley Tucci, Helen McCrory and Jennifer Ehle.

"I can't imagine anyone else playing Kate's role because not only does she like getting her hands dirty, but she scrubs up extremely well," Rickman joked.

"She's the most sensitive, intelligent actor and wonderful with the other actors and I think she has a wonderful chemistry with Matthias."

A Little Chaos marks Rickman's big-screen return as a director. He last sat in the director's chair for The Winter Guest in 1997.

"I've been directing a lot in the theatre in the intervening time," he said. "Once you start directing, you're always thinking of pitches so it's really just about organising your life to be able to take on whatever it is, like a year and a half off."

A Little Chaos opens in UK cinemas on April 17 2015.