Depp is suing U.K. tabloid The Sun, its publisher News Group Newspapers (NGN), and its executive editor Dan Wootton over a 2018 story that branded him a "wife beater" in relation to allegations Heard made against her ex-husband, which he denies, after they split in May 2016.
According to Deadline.com, in her fourth day of testimony in the trial, the "Aquaman" actress described her ex as a "remarkable man" when he is "clean and sober" but said the "other side of him was a monster."
The court was told that in a series of text messages to her mother Paige in March 2013, the 34-year-old described Depp, 57, as "violent and crazy" and added, "I'm heartbroken that this is who I love."
The star was giving evidence over an alleged incident that she claims took place in March 2013, during which she says the "Pirates of the Caribbean" star hit her with the back of his hand, drawing blood, after an argument about a painting by her ex-partner Tasya van Ree.
The Sun's lawyer Sasha Wass said that in texts Heard described the situation as "terrible," adding, "He's nuts, mum. Violent and crazy. I'm heartbroken that this is who I love."
Discussing her mindset when sending the messages, the actress told the court, "I was so in love with Johnny at that time. We had had a wonderful year together where he was sober and clean and that is how I got to know him. And Johnny, when he was like that, (is) generous, loving, he is a remarkable man when he is like that."
"I loved him and I didn't want to lose that… the other side of him was a monster, but I always held out hope that he would get clean and sober."
Wass also told the court that Heard was unwilling to tell her father about her ex's alleged violence, with the star explaining, "I felt safe to tell my mother, but I didn't know how my dad would react. I had never been in this situation before and I didn't know if he would react violently… to Johnny. I didn't want to make it worse."
The blockbuster trial is expected to conclude next week, after three weeks that have seen both Depp and Heard give evidence and attend each day of proceedings. The actor denies he was violent towards his ex-wife on 14 occasions and claims she was violent towards him.