Hollywood star Johnny Depp wrote on a wall with blood from his severed finger tip during a long and violent confrontation with his ex-wife Amber Heard in Australia, London’s High Court has heard at his libel case against a British tabloid.

Depp told the court he suffered “some species of nervous breakdown” during a row with actress Heard but denied he had violently attacked her and accused her of cutting his finger by throwing a bottle at him.

The revelations came on the third day of Depp’s appearance in the witness stand as he sues the publisher of Britain’s Sun tabloid, News Group Newspapers, over an article in which it labelled the actor a “wife beater”.

Throughout the case, Depp has rejected all accusations that he was violent towards his former wife, saying that they were part of hoax created by Heard as an insurance policy.

“She was building a wonderful dossier, an insurance policy for when we did break up,” he said.

Bianca Butti and Amber Heard depart after attending the libel case between Johnny Depp and The Sun Newspaper in London. Photo: Getty

The court heard that Depp was in Australia in March 2015 to film Pirates of the Caribbean a month after the couple married.

Heard had flown to join him from London, where she had been making a movie with co-star Billy Bob Thornton.

The Sun’s lawyer Sasha Wass said Heard suffered a three-day ordeal at Depp’s hands in the rented house where the actor was staying after she became angry at him because he had been drinking to excess and taking drugs.

Consumed with jealousy about Heard and Thornton, Depp attacked her, constantly swigging from a bottle, Ms Wass said.

He slapped Heard across the face, smashed her head against a fridge, and she barricaded herself in her bedroom to escape him, the court was told.

Ms Wass said Depp spat in her face, grabbed her by the throat and told her it would be easy to crush her neck.

“Fabricated and vicious,” Depp replied, rejecting all the accusations.

“I vehemently deny it and go as far as to say it was pedestrian fiction.”

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He agreed the couple had a row on the final day that began because he wanted Heard to sign a post-nuptial agreement, and he had not been drinking until that point.

Depp said Heard threw two vodka bottles at him, the second of which “severed my finger and crushed my bones”.

“That is when I began what I feel was perhaps some species of a nervous breakdown,” he told the court.

He said he began to write messages on the wall in blood with his severed finger, before then using paint. One message on a mirror said: “Starring Billy Bob, Easy Amber”.

Ms Wass said the house was a scene of “carnage” with paint everywhere, and windows and the television smashed.

It caused $US100,000-$US150,000 ($143,626-$215,438) of damage, according to Depp’s assistant, the lawyer said.

By December 2015, Depp was regularly using violence against Heard, according to Ms Wass.

He replied the problem was that he ran away from fights.

At their LA penthouse, Ms Wass said when Heard stood up to Depp, he chased her, saying “you think you are a f***ing tough guy?”, slapped, then headbutted her in “an uncontrollable rage”, pulled out clumps of her hair and said he was going to kill her.

“It’s a lie,” Depp said.

Shown pictures of Heard with two black eyes, Depp said he had tried to grab her eyes while defending himself and he could have headbutted her accidentally.

-AAP