The Aquaman actress, 34, has accused Mr Depp, 57, of both verbal and physical abuse throughout their relationship – allegedly punching, slapping, kicking, headbutting and choking her, as well as displaying “extremely controlling and intimidating behaviour”.
Mr Depp, however, says he was not violent towards Ms Heard, claiming it was she who was violent to him.
Ms Heard is giving evidence at the Royal Courts of Justice in London about 14 allegations of domestic violence which The Sun’s publisher News Group Newspapers (NGN) relies on in its defence of an April 2018 article that called Mr Depp a “wife beater”.
On Tuesday, Ms Heard told the High Court she heard a “rumour” Mr Depp pushed his former partner Ms Moss down a flight of stairs, which she said was “fresh in her mind” when the Pirates of the Caribbean star allegedly attempted to do the same to her sister, Whitney Henriquez, in March 2015.
On her second day in the witness box, Ms Heard also said actor James Franco asked her “What the f***?” when he saw her face the day after an alleged incident on May 21, 2016, when she claims Mr Depp threw her own mobile phone at her, hitting her in the face.
She was also questioned over alleged affairs with Mr Franco and Tesla founder Elon Musk – which Ms Heard denies – as well as the now-infamous “defecation incident”, when faeces were found in the couple’s bed after Ms Heard’s 30th birthday party in April, 2016.
Ms Heard said she returned to live with Mr Depp after a March 2015 incident in Australia – which she describes as a “three-day hostage situation” when Mr Depp lost the tip of his finger in disputed circumstances – only because she thought it was “bad enough that he would actually get clean and sober for once and this was the last time”.
She also claimed Mr Depp “hit both myself and my sister” during the “stairs incident” in Los Angeles in March, 2015 – and denied hitting Mr Depp other than in “self-defence”.
The actress said she “did strike Johnny that day in defence of my sister”, adding: “He was about to push her down the stairs and, the moment before that happened, I remembered information I had heard (that) he pushed a former girlfriend – I believe it was Kate Moss – down the stairs.
“I had heard this rumour from two people and it was fresh in my mind.”
Ms Heard added: “In a flash, I reacted in defence of her.”
The court also heard text messages between Ms Heard and Mr Musk from May 22, 2016, in which Mr Musk offered to arrange “24/7 security” for Ms Heard.
The billionaire told Ms Heard: “The offer would stand, even if you never wanted to see me again… anyway, sorry for being an idiot. The radio silence hurts a lot. It only matters because I really like you.”
But Ms Heard told the court she “wasn’t even in communication with Elon until 2016”.
CCTV footage of Ms Heard in a lift to her penthouse with Mr Franco on May 22 2016, at about 11pm, was played to the court.
Ms Heard said: “We were talking. He was saying to me ‘Oh my god, what happened to you?’
“He saw my face… when I let him in. He saw my face and he said ‘What the f***?’”
Ms Heard said the suggestion she left faeces in the bed she shared with Mr Depp at the Los Angeles penthouse was “absolutely disgusting”.
She said it is “unimaginable” that one of her friends left the excrement after her 30th birthday party in April 2016, and that she “can’t fathom what adult would ever do such a thing”.
The actress also insisted she had visible injuries in the days following the alleged incident on May 21, 2016 – despite evidence from “a number of witnesses” who claim they saw Ms Heard in the following days without any visible marks.
Ms Heard’s evidence will continue on Wednesday morning, before her friends Melanie Inglessis and Joshua Drew are due to give evidence by videolink from LA in the afternoon.
Mr Depp is suing NGN and The Sun’s executive editor Dan Wootton over the publication of an article on April 27, 2018, with the headline: “Gone Potty: How can JK Rowling be ‘genuinely happy’ casting wife beater Johnny Depp in the new Fantastic Beasts film?”
His lawyers say the article bore the meaning there was “overwhelming evidence” Mr Depp assaulted Ms Heard on a number of occasions and left her “in fear for her life”.
NGN is defending the article as true, and says Mr Depp was “controlling and verbally and physically abusive towards Ms Heard, particularly when he was under the influence of alcohol and/or drugs”.