Blake Lively has filed a legal complaint against It Ends With Us co-star Justin Baldoni, alleging sexual harassment and a campaign to "destroy" her reputation.

According to the legal filing, she accuses Mr Baldoni and his team of attacking her public image following a meeting in which she brought along her actor husband, Ryan Reynolds, to address "repeated sexual harassment and other disturbing behavior" by Baldoni and a producer on the movie.

Mr Baldoni's legal team told the BBC the allegations are "categorically false" and said they hired a crisis manager because Ms Lively had threatened to derail the film unless her demands were met.

In the romantic drama, Ms Lively plays a woman who finds herself in a relationship with a charming but abusive boyfriend, played by Mr Baldoni.

The meeting between Ms Lively and Mr Baldoni, together with others involved in the movie's production, took place on 4 January this year, and it aimed to address "the hostile work environment" on set, says the legal filing.

Ms Lively's husband, Deadpool star Mr Reynolds, who did not appear in It Ends With Us, joined her at the showdown, according to the legal complaint, which is one step before a lawsuit.

Mr Baldoni, 40, attended the meeting in his capacity as co-chairman and co-founder of the company that produced the film, Wayfarer Studios. He was also the film's director.

In the legal complaint, Ms Lively's lawyers allege that both Mr Baldoni and the Wayfarer chief executive officer, Jamey Heath, engaged in "inappropriate and unwelcome behavior towards Ms Lively and others on the set of It Ends With Us".

In the filing to the California Civil Rights Department, a list of 30 demands relating to the pair's alleged misconduct was made at the meeting to ensure they could continue to produce the film.

Among them, Ms Lively, 37, requested that there be no more mention of Mr Baldoni and Mr Heath's previous "pornography addiction" to Ms Lively or to other crew members, no more descriptions of their own genitalia to Ms Lively, and "no more adding of sex scenes, oral sex, or on camera climaxing by BL [Blake Lively] outside the scope of the script BL approved when signing onto the project", says the complaint.

Ms Lively also demanded that Mr Baldoni stop saying he could speak to her dead father.

Ms Lively's legal team further accuse Mr Baldoni and Wayfarer Studios of leading a "multi-tiered plan" to wreck her reputation.

She alleges this was "the intended result of a carefully crafted, coordinated, and resourced retaliatory scheme to silence her, and others from speaking out about the hostile environment that Mr Baldoni and Mr Heath created".

Responding to the legal complaint, Mr Baldoni's lawyer, Bryan Freedman, said on Saturday: "It is shameful that Ms Lively and her representatives would make such serious and categorically false accusations against Mr Baldoni, Wayfarer Studios and its representatives."

Mr Freedman accused Ms Lively of making numerous demands and threats, including "threatening to not show up to set, threatening to not promote the film", which would "ultimately leading to its demise during release, if her demands were not met".

He alleged that Ms Lively's claims were "intentionally salacious with an intent to publicly hurt and rehash a narrative in the media".

In a statement via her attorneys to the BBC, Ms Lively said: "I hope that my legal action helps pull back the curtain on these sinister retaliatory tactics to harm people who speak up about misconduct and helps protect others who may be targeted."

She also denied that she or any of her representatives planted or spread negative information about Mr Baldoni or Wayfarer.

The film was a box-office hit, although some critics said it romanticised domestic violence.

Soon after the release date in August, Mr Sklenar hinted in an Instagram post at rumours of a rift between Ms Lively and Mr Baldoni.

Speculation of a falling out only grew when they did not appear together on the red carpet, however, neither star had spoken openly about it.

It Ends With Us tells the story of Boston florist Lily Bloom, played by Ms Lively, as she navigates a love triangle between her charming but abusive boyfriend, Ryle Kincaid, played by Mr Baldoni, and her compassionate first love, Atlas Corrigan, played by Brandon Sklenar.

It is based on a best-selling novel by Colleen Hoover. The 45-year-old author has previously said her inspiration was domestic abuse her mother endured.

In an interview with the BBC at the film's premiere in August, Ms Lively said she had felt the "responsibility of servicing the people that care so much about the source material".

"I really feel like we delivered a story that's emotional and it's fun, but also funny, painful, scary, tragic and it's inspiring and that's what life is, it's every single colour," said the actress.

Ms Lively, who is also credited as a producer, told the BBC she felt the film had been made "with lots of empathy".

"Lily is a survivor and a victim and while they are huge labels, these are not her identity," said Ms Lively. "She defines herself and I think it's deeply empowering that no one else can define you."