It Ends With Us actor and director Justin Baldoni has sued his co-star Blake Lively and her husband, Deadpool actor Ryan Reynolds, for defamation and extortion on Thursday in the latest move in a bitter legal battle surrounding the dark romantic drama.

The suit filed in federal court in New York by Baldoni and production company Wayfarer Studios seeks at least 400 million US dollars (£327 million) for damages that include lost future income.

It alleges that Lively and Reynolds hijacked the production and marketing of It Ends With Us and manipulated the media to smear Baldoni and others on the production with false allegations of sexual and other harassment.

Justin Baldoni, right, and Blake Lively in a scene from It Ends With Us (Nicole Rivelli/Sony Pictures via AP)

“This is a case about two of the most powerful stars in the world deploying their enormous power to steal an entire film right out of the hands of its director and production studio,” the suit says.

“Then, when Lively and Reynolds’ efforts failed to win them the acclaim they believed they so richly deserved, they turned their fury on their chosen scapegoat.”

The lawsuit comes about two weeks after Lively sued Baldoni and several others tied to the film, alleging they retaliated against her for coming forward about her treatment on the set.

Her lawyers called Baldoni’s new lawsuit “another chapter in the abuser playbook”.

“This is an age-old story: A woman speaks up with concrete evidence of sexual harassment and retaliation and the abuser attempts to turn the tables on the victim,” they said in a statement on Thursday night. “This is what experts call DARVO. Deny. Attack. Reverse Victim Offender.”

It Ends With Us, based on the bestselling 2016 novel by Colleen Hoover, was released in August and exceeded box office expectations with a 50 million US dollar (£40.8 million) debut. It begins as a standard romantic drama before taking a dark turn into domestic violence.

The fallout in its aftermath has made major waves in Hollywood and led to discussions of the treatment of female actors both on sets and in media.

Justin Baldoni, left, and Blake Lively in another scene from It Ends With Us (Nicole Rivelli/Sony Pictures via AP)

“Heartbreakingly, a film that Baldoni envisioned years ago would honour the survivors of domestic violence by telling their story, with the lofty goal of making a positive impact in the world, has now been overshadowed beyond recognition solely as a result of Lively’s actions and cruelty,” the lawsuit says.

Lively’s allegations of sexual and other harassment followed by retaliation are utterly false, Baldoni’s suit alleges.

“Lively was so close and comfortable with Baldoni that she freely breastfed in front of him during meetings,” the suit says.

She would later take moments like these that she encouraged and recast them as sexual harassment and misconduct, his lawsuit alleges.

Lively’s December 31 lawsuit came just hours after Baldoni sued the New York Times for libel, alleging the paper worked with Lively to smear him.

The New York Times said it stood by its reporting and planned to “vigorously defend” against the allegations.

Baldoni’s new suit also says that counter to Lively’s allegations, every request she made for an intimacy coordinator to help with sensitive scenes in the film was honoured.

Blake Lively poses for photographers upon arrival at the UK Gala Screening for the film (Scott A Garfitt/Invision/AP, File)

It focuses especially on a a birthing scene, saying Lively’s contention that she was “mostly nude” with non-essential people present including the film’s financier was “knowingly false”.

Baldoni says that at another point during the production because he has back problems, he privately and politely asked Lively her weight so that he could work with his personal trainer to be able to safely lift her in the film.

Reynolds later “swore at Baldoni and accused him of fat-shaming his wife”, the suit says.

“In fact, Lively had earlier expressed insecurity about her postpartum figure, and Baldoni made every attempt to genuinely reassure her,” his lawsuit says.

Baldoni took a backseat in promoting the film while Lively took centre stage along with Reynolds, who was on the press circuit for Deadpool & Wolverine at the same time.

Ryan Reynolds as Deadpool/Wade Wilson, left, and Hugh Jackman as Wolverine/Logan in a scene from Deadpool & Wolverine (20th Century Studios/Marvel Studios via AP)

The backlash against Baldoni led to his being dropped by his agency WME, which also represents both Lively and Reynolds.

The suit alleges Reynolds was responsible for this, saying that he approached a WME executive at the Deadpool & Wolverine premiere and “expressed his deep disdain for Baldoni, suggesting the agency was working with a ‘sexual predator’”.

“Lively knew full well that making those allegations would be a career death sentence for Plaintiffs, especially given that Baldoni has lived his private and public life as an impassioned advocate for gender equality and healthy masculinity,” his lawsuit says.

But Lively’s lawyers’ statement said that evidence would show that other cast members had similar experiences with Baldoni.

“In short, while the victim focuses on the abuse, the abuser focuses on the victim,” the lawyers said.

“The strategy of attacking the woman is desperate, it does not refute the evidence in Ms Lively’s complaint, and it will fail.”

Justin Baldoni attends the world premiere of It Ends with Us at AMC Lincoln Square in New York (Evan Agostini/Invision/AP, File)

Baldoni’s lawsuit says Lively’s cruelty even extended to her serving the papers from her lawsuit on Baldoni and his co-defendants in the days after she filed it during the onset of the wildfires that have ravaged the Los Angeles area, saying that on a day when they were “gathering their kids and pets, preparing ‘go bags’ and monitoring evacuation orders while fearing for their homes, Lively – from the safety of her penthouse in New York – deployed process servers”.

Baldoni’s lawyer, Bryan Freedman, said in a statement on Thursday that “this is a battle she will not win and will certainly regret”.

“Ms Lively will never again be allowed to continue to exploit actual victims of real harassment solely for her personal reputation gain at the expense of those without power,” he said.