Gwyneth Paltrow to be Kidman's wife

The 'Iron Man' actress has signed on to replace Charlize Theron in 'The Danish Girl', an adaptation of a novel about the first post-operative transsexual.

The film follows Danish artists Einar and Greta Wegener who found success after Einar stood in for a female model that Greta was set to paint. As their work gained popularity, Greta encouraged her husband to continue to adopt a female guise.

This eventually led to Einar undergoing a sex change operation in 1931, shocking the world and threatening their marriage.

Anand Turker is set to direct the film, which screenwriter Lucinda Coxon is adapting from David Ebershoff's novel of the same name.

Nicole previously won an Oscar for playing a lesbian in 'The Hours', while Gwyneth saw her character in 'Shakespeare In Love' disguise herself as a man in order to fulfil her acting dreams.

Last week, Nicole said she actively sought out "extreme" film choices and explored all aspects of love, sex and marriage.

She said: "In the end I hope my life will be a mix of extreme love and bold artistic choices. I've never wanted to be safe. I've never chosen safe relationships. And I've never chosen safe films."