Depp’s lawyers reportedly hope testimony from Moss, 48, who dated the actor in the 1990s, will pour ice cold water on Heard’s courtroom suggestion that he is a domestic abuser.
His legal team were seen appearing to celebrate when Heard, 36, mentioned Moss in testimony, as she described hearing a rumour that Mr Depp had pushed the model down a flight of stairs.
A source close to Depp said Moss is scheduled to appear via videolink.
They believe she will say he “caught her and tended to after she tripped on stairs in flip flops during a vacation in Jamaica”.
Depp, 58, is suing Heard for libel over a December 2018 article she wrote in the Washington Post, which his lawyers say falsely implies he abused her while they were together.
The Pirates of the Caribbean actor claims he was defamed by the op-ed even though it never mentioned his name.
Earlier on Tuesday, Virginia’s Fairfax County Circuit Court was told Heard was “on the precipice of a meteoric rise” before the negative press caused by allegedly defamatory comments made by Depp’s legal team.
Entertainment industry expert Kathryn Arnold said she believed the actress lost out on up to $50million (£40million) after her claims of abuse by her former partner were labelled a “hoax” by Adam Waldman in 2020.
Giving testimony in the final days of the six-week defamation case, Ms Arnold said Depp’s multiple public lawsuits and “erratic behaviour” contributed to his career decline before the publication of Heard’s article.
The piece had had “zero” effect on his reputation or damages.
Ms Arnold added: “Amber has had a pretty long career for someone who is pretty young still...she had a consistent working actor’s career.
“Her career was following a very nice steady rise and was on the precipice of a meteoric rise with Aquaman and Aquaman 2, prior to the (defamatory) statements.”
She added that the resulting backlash online had made it “hard for (brands) to work with Amber on any level because of the negativity brought to their product or service or film” and that the campaign was ongoing.
“In the public it’s been very negative, in the industry they like her work but they can’t work with her right now because every time her name is mentioned, the negativity flares up again.”
Ms Arnold said that despite questions over Heard not being hired for Aquaman 2, the film’s director James Wan and star Jason Momoa remained “committed” to the actress.
She added that Heard was “comparable” to actors including Momoa, Wonder Woman star Gal Gadot and Zendaya, all of whom have gone on to secure lucrative contracts with brands and other film and television.
Closing arguments in the case are expected to be given on Friday.
Jurors have previously heard multiple allegations of both physical and sexual abuse against Depp, with testimony provided by people including Heard’s sister Whitney, friend Raquel Pennington, and another of his former partners, Ellen Barkin.
In video deposition played to the court last week, Ms Barkin claimed Depp was controlling during their short relationship.
Several famous faces appeared on the initial witness lists for the trial, including Tesla founder Elon Musk and actors Paul Bettany and James Franco, though none have been called on.