Winona Ryder's difficult Black Swan role

Winona Ryder found it hard to be so nasty to Natalie Portman on the set of 'Black Swan' because she had worked so intensively for the role.

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."