Amber Heard's lawsuit explained: what it means to have a "nudity rider".

Amber Heard is suing the producers of London Fields — a film spiked due to multiple legal issues — for ‘sexploitation’ after an “explicit pornographic sex scene” was secretly filmed using her body double.

The film, which is an adaptation of Martin Amis’ novel of the same name, was pulled from the Toronto International Film Festival in 2015 after its director Mathew Cullen accused producer Christopher Hanley and his wife Roberta, the screenwriter, of failing to pay him and honour his vision for the final cut.

Several of the films high-profile stars, including Heard, her ex-husband Johnny Depp, Billy Bob Thornton and Jim Sturgess backed him up and threatened to boycott the festival.

Cullen sued the Hanleys, they sued him back, and while they were at it slapped Heard with an additional $10 million lawsuit for failing to meet her contractual obligations—she is now counter-claiming against them.

Confused? Let us explain.

According to The Hollywood Reporter, the 30-year-old actress now alleges the Hanleys violated her 'nudity rider', a clause in her contract which stated the level of nudity she was comfortable with on-screen and whether or not she would participate in sex scenes.

"Amber Heard is the latest victim of this lascivious and sexploitive couple," the suit stated.

"After reading the script, she insisted on specific restrictions about nudity and sex scenes in the film as a condition to agreeing to appear in the movie.

"Hanley ... expressly agreed to Heard's terms, and they were memorialised in the nudity rider to her contract."

A "nudity rider", often referred to as the "nudity clause" is a paragraph or section in a legal contract which states which — if any — body parts an actor or actress agrees to show on film and whether or not a body double or props can be used should they opt out of on-screen sex.

They are common practice in Hollywood and union guidelines require director's to itemise exactly what will be shown and how, well in advance of filming.

Heard says she conferred with Cullen about the film's sex scenes and was happy with his "Director's Cut", but the Hanleys created their own tawdry edit featuring a "pornographic" scene filmed in secret with a body double.

It allegedly involved a female police officer, a female prisoner and a police baton on the hood of a police car which Heard "would never have agreed to do herself".

"The body double footage was designed and intended to leave anyone who saw the images with the distinct impression that it was Heard," the suit said.

On top of that, it's alleged the Hanleys demanded to keep 'continuity photos' after filming wrapped potentially featuring Heard "in various states of undress during wardrobe changes" with "no legitimate business purpose" for doing so.

"The Hanleys' prurient interest in exploiting Heard — both on and off camera — speaks volumes about their values," the suit said.

The couples' lawyer Matthew Rosengart dismissed Heard's claims as "a work of fiction" and the latest in a series of "fantastical allegations she has made," disturbingly referencing her "high-profile" divorce, the catalyst for which was Depp's alleged ongoing domestic abuse.