Olivia Williams has described her Anna Karenina co-star Keira Knightley as a "phenomenal actress".
The pair will appear together in the upcoming adaptation of Leo Tolstoy's classic novel which is directed by British filmmaker Joe Wright and which will star Aaron Johnson and Jude Law.
Olivia said Keira would have no problem taking on the challenging title role.
She added: "In some films you're on your own but in a Joe Wright film you're not on your own, it's a genuinely collaborative event and I think that she's a phenomenal actress with or without this incredible ensemble behind her."
Olivia, who worked with Joe on the action thriller Hanna, said she was delighted to be collaborating with him again.
"This movie and this role carries the weight of history behind it and I really believe Joe's the man for the job. I think he said, 'I'm sick of realism'. He's not looking to turn Anna Karenina into a kitchen sink drama.
"There is a grandiosity to it and I think our understanding of the time and the mores and how people had to behave, it's important that there's a huge monolith of society and convention she has to smash through and doing mumbling, naturalistic performances would be unrealistic for that."
:: Hanna is out on DVD now.