For Depp, they say, has struggled to cope with the 'terrible accusations' made against him by his former wife, the model-turned-actress Amber Heard, who sensationally branded him a wife-beater as pictures showing her with a bruised face circulated on the internet.
So far, Depp has remained silent about the explosive allegations, even though they threaten to derail his stellar career.
Today, however, The Mail on Sunday can reveal he is attempting to clear his name with a High Court case in London against a newspaper that reported Ms Heard's allegations earlier this year.
And he has told friends: "I'm not sick. I'm not battling anything, other than the smears that I'm determined to prove are false."
Depp is suing The Sun for libel, over a story calling him a wife-beater, and which also criticised JK Rowling for standing by the actor after he was cast in a film spin-off of her Harry Potter books.
He has been accused of hurling a mobile phone with such force that it injured Ms Heard during an altercation in May 2016 in which it is claimed their apartment was damaged. But in court papers seen by this newspaper, Depp's legal team denies absolutely that the star assaulted Ms Heard.
The High Court papers cite depositions from two Los Angeles police officers, who appear to contradict Ms Heard's version of events.
They say they arrived at the couple's home 25 minutes after the alleged attack, yet saw no damage to the property, adding that a crying Ms Heard told them she wasn't hurt and did not need medical attention. Nor did they see injuries or swellings on her face.
The papers show that Depp denies Ms Heard's claim that he was either high or drunk on May 16, when he had entered the apartment to collect some of his belongings.
His lawyers claim he brought two of his security team along with him because he 'was concerned' about what Ms Heard would do.
They too appear to contradict her version of events, claiming that Depp was not in fact physically close to his wife during the incident.
The court documents state that one of the guards, who had been waiting outside the door when Depp entered the penthouse, rushed in when Ms Heard began shouting.
'Immediately upon opening the door, the security guards observed [Depp] standing in the kitchen areas, far away from Ms Heard,' the lawyers say in the papers. 'At that moment, Ms Heard yelled, 'Stop hitting me, Johnny' into the phone.
The claimant was not hitting Ms Heard. Ms Heard was standing in front of the sofa about 25 feet away.'
Ms Heard was then said to have looked visibly shocked and feigned crying.
The court document states that she then began talking in the past tense after speaking in the present and said: 'He hit me with a phone' and, 'That's the last time you hit me, Johnny.'
She then screamed into the phone for a friend to call police.
Ms Heard separated from Depp that same month after describing a disturbing history of domestic abuse and filing a temporary restraining order.
In her own dramatic account of the row, she has described how Depp aimed the phone at her from close range, saying that he deliberately wound up his arm 'like a baseball pitcher' to throw it at her head, 'striking her cheek and eye with great force'.
The scene, she alleged, was chaotic, with Depp screaming and breaking things, including chandeliers, and spraying wine before finally storming out. Her friend Raquel Pennington has publicly backed this account of events.
Neither Ms Heard nor her representatives have commented on the new High Court case, for which no date has been set. The Sun has said that Ms Heard's claims are backed by overwhelming evidence and will be vigorously defended with testimony from numerous witnesses and taped evidence.
