Kate Moss has a touching reason why she chose to speak up during Johnny Depp and Amber Heard's defamation trial.

Among the witnesses who testified in the recently-ended legal battle between Depp and Heard, Moss seemingly had the biggest role as she ultimately debunked one of the actress's claims against the actor.

Now, she spoke candidly about her choice in an interview with the BBC radio show "Desert Island Discs." The news outlet asked her why she defended Depp and John Galliano, a fashion designer who was found guilty of making racist and antisemitic comments in 2011.

"I know the truth about Johnny. I know he never kicked me down the stairs. I had to say that truth," she said.

As for Galliano, the model explained that the fashion designer is not a bad person although he had an alcohol problem. She reportedly believes that people are not themselves when they are drunk and tend to say things they would not say if they were sober.

Kate Moss' Testimony Saved Johnny Depp

Her revelation came out after Heard claimed that Depp pushed the model down a staircase when they dated in the 1990s.

Heard also mentioned Moss in her statement during the 2020 UK libel trial between Johnny Depp and The Sun. At that time, Depp's lawyer Eleanor Laws countered the claims and said that she never mentioned Moss in any document. Thus, they accused her of making things up as she went along.

In the defamation trial, Heard claimed that she thought of Kate Moss and the stairs when Depp reportedly swung at her sister.

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In the viral video shared on Reddit,  Depp's lawyers looked victorious immediately after the actress mentioned Moss since it allowed the representatives to bring her in as a rebuttal witness.

"She threw herself in the line of fire," she said, referring to her sister Whitney. "She was trying to get Johnny to stop. Her back was to the staircase, and Johnny swings at her ... I don't hesitate and wait, I instantly think of Kate Moss and stairs."

Moss, indeed, testified to support Depp and disprove Heard's narrative that he has a history of abuse. Although she and the "Pirates of the Caribbean" actor had an infamous screaming session in public before their split, no reports about the actor being abusive to her ever emerged.

She eventually revealed that she has always been impressed by his kindness, even after they broke up.

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