Winona Ryder found 'Black Swan' "difficult" to film.
The 39-year-old actress - who plays the supporting role of ageing ballet dancer Beth MacIntyre in the Darren Aronofsky-directed project - found being nasty to its lead star Natalie Portman tough because she knew how much she had worked to perfect the role of psychologically-troubled Nina.
Speaking after Natalie had picked up the Golden Globe award for Best Actress for her performance in the film, she said: "It was very difficult because I love Natalie so much and I'm so thrilled with all the accolades, she's just so deserving and she works so hard for it."
Winona - who currently stars in comedy movie 'The Dilemma' with Vince Vaughn and Kevin James - added she didn't realise Natalie had taken the part so seriously until she came up to do play her supporting character in the film.
She to UK TV show 'Daybreak': "I didn't even realise, I came in for my part and she had been training for a year. It was a wonderful little juicy hamburger of a role."