Bill 'Beano' Hanti, who was in a band known as 'The Kids' with Depp in the 1980s, revealed his hostile feelings for Heard in the new two-part documentary Johnny vs Amber, which will stream on 18 December.
The Pirates of the Caribbean star joined the band as a guitarist when he was 17 years old before putting his musical career on hold to pursue acting.
Recalling Depp's journey since then, Hanti described how Depp's former partner of 14 years and mother to his children Vanessa Paradis was a 'beautiful soul'.
In a clip from the upcoming documentary, Hanti says: "He had something special with Vanessa and he f****d it up."
Going on to discuss Heard, who met Depp in 2009 on the set of The Rum Diary, he explained: "She just saw him coming. She got the opportunity to be a part of that film and she worked it.
"Ruined his life, it really did. Look at it, it totally f****d his career over. Cost him his friends. Part of his family.
"She got inside John's head and made him absolutely crazy to the point where he was drinking and drugging, to the point of insanity."
The documentary series is set to tell the story from two 'polarised perspectives' of Heard and Depp's divorce and legal battles, one representing Depp's account of events and the other representing Heard's.
Sasha Wass QC, who represented NGN in the libel action brought by Depp, revisits the evidence she used during the trial.
She says in the documentary: "My job in this case was to prove a pattern of abusive behaviour," adding that 'the story the texts tell is that drugs, alcohol, regret and apologies played a very large part in their relationship'."
Depp's episode is said to 'portray that he found himself married to a Machiavellian liar who would stop at nothing to protect her image'.
Speaking about the series, Charlotte Reid, VP Head of Commissioning, L&E, at Discovery UK said: "The story of what happened between Johnny and Amber continues to be hugely divisive, between fans and the public at large.
"We set out to make a documentary that would explore the story from each of their perspectives, so the viewer can go beyond the headlines, understand who they are, and decide who they should believe in this complex human story."
Johnny vs Amber is available to stream from Saturday 18 December exclusively on Discovery+.
Words: Daisy Phillipson