The star, who is best known for her portrayal of Vesper Lynd in the James Bond film Casino Royale with Daniel Craig, was due to play the lead role in A Patriot, but the production was abandoned in October 2019.

Green, 42, is suing White Lantern Films and SMC Speciality Finance for the $1m (about £808,000) fee she says is still owed, despite its cancellation.

White Lantern is bringing a counterclaim against the French actress, alleging she undermined the independent film's production, made "excessive creative and financial demands", and had expectations that were "incompatible" with the film's low budget.

The producers have cited WhatsApp messages from Green in which she described one producer as a "f****** moron" who should be fired and another as "evil". She also allegedly described funders for the movie as "a*seholes" and some proposed crew members as "sh*tty peasants". The actress addressed these messages later in her evidence.

Entering the witness box at the High Court on Monday, the third day of the hearing, Green said the messages were an "emotional response" after being lied to about where a film project was due to be shot.

The court heard that in a message to her agent, the actress said: "I am very worried, they are super weak and stupid."

Max Mallin KC, for White Lantern Films, said Green's message was "presumably" about producer Adam Merrifield and writer and director Dan Pringle.

"I don't know... it's my Frenchness coming out sometimes," Green said.

She added: "Sometimes you say things you don't actually mean, of course they are not weak and stupid."

Green first told how making quality productions was her "religion" and said abandoning A Patriot would have been like abandoning her "baby".

In her written evidence to the court, Green said she "fell in love" with the film, in which she was cast as soldier Kate Jones, after reading writer and director Dan Pringle's "brave and daring" script.

"I believed and still do that the film had the capacity to really wake people up and help them to see that the devastation of our world would eventually trigger resource wars and massive migration," she said in the statement.

Green added in court: "As I have said repeatedly, I fell deeply in love with this project - not only the role, but also the message of the film.

"I couldn't imagine abandoning the film, as it would have been like abandoning my baby. It still feels that way."

Producers say Green had 'animosity'

Green said the script for the film was "one of the best scripts I have ever read" and that she was excited to play the role of a soldier, which she had never done before. She cited the film being about climate change as an issue "dear to my heart and important".

The actress also discussed some of her other work, telling the court: "I don't care about the money. I live to make good films, it's my religion."

Max Mallin, representing White Lantern, previously claimed Green had an "animosity" towards a vision for the film held by one of its executive producers, Jake Seal.

Read more on Sky News:
Why is Rick Astley suing rapper Yung Gravy?
Buffy star shares what most scares her and how she moved on from 'toxic' 90s set

The barrister said that in exchanges on WhatsApp with her agent and the film's director, Green claimed Seal was planning to make a "cheap B movie" and described him as "the devil" and "evil".

Mr Mallin asked Green if she remembered sending a different text message, suggesting the film under Mr Seal would be a "B-sh*tty-movie"; she said she did.

Green told the court: "I never wanted this to be a B-movie but I realised more towards the end that it was going to happen."

She continued: "I had several opportunities to walk away from this project but at the time I felt like I had an armour, the strong crew members around me.

"I thought we had these strange producers but a strong crew so we could still make something good quality, but I was probably naive."

Click to subscribe to Backstage wherever you get your podcasts

The move from Ireland

In her witness statement, Green said her initial confidence in the film dwindled following delays and its move from Ireland to a studio outside London, and that she felt she had been "deceived".

Denying allegations that she was not prepared to go ahead with the film, she said: "In the 20 years that I have been making films, I have never broken a contract or even missed one day of shooting.

"Nor have I been late or done anything but give 100% heart, body and soul to every project I have ever been involved in."

She added: "Why on earth would I sabotage a project that I loved and that I risked my reputation on? It makes no sense at all."

'Nothing against peasants'

Green also apologised for "inappropriate language" and "some horrible things" expressed by her in emails and texts in August and September 2019.

She said one message was an "emotional response" after finding out she had been "lied to" about the move from Ireland.

The actress also told the High Court she has "nothing against peasants" when questioned about the word being used in one of her messages.

"I have nothing against peasants, I didn't want to work with a sub-standard crew," she said. "I wanted to work with a high-quality crew who just wanted to be paid standard industry rates."

A Patriot was also due to feature Game Of Thrones star Charles Dance and Twister star Helen Hunt, with Oscar winner Kathy Bates attached too at one point.

Green is due to finish giving evidence on Tuesday and a ruling on the case is expected at a later date.