Kate Winslet claims filming 'Labor Day' was unpredictable.

The Oscar winning actress says she never knew what director Jason Reitman was going to do next on the set of her latest movie, which had its premiere on Monday (14.10.13) as part of the BFI London Film Festival.

She told BANG Showbiz: ''We had Jason Reitman guiding us, he's very specific, he knows exactly what he wants. As actors sometimes we literally didn't know what he would do next.

''I think what he wanted for the audience to feel, as well, is you shouldn't know what was going to happen next at all. That was very much the case on set.

''Initially it was a little bit of an adjustment I think for us all to make, but it was great to have that guidance and that structure actually because [it] leant itself to the tone of the film.''

The 38-year-old stars as a single mother who unwittingly invites an ex-convict, played by Josh Brolin, into the home she shares with her son (Gattlin Griffith) on the US Labor Day.

Speaking on the red carpet, Kate - who wore a full length red Jenny Packham gown with black open toe heels - said about preparing for her role: ''It doesn't matter how much you think about a character and think about the film before you get there, on day one it's as though you don't know your name, you don't know your characters name, you don't know how to act anymore - you think that everyone thinks you're stupid.''