Kate Moss is expected to testify for Johnny Depp against Amber Heard on Wednesday

• Kate Moss is expected to testify on Wednesday in Johnny Depp's trial against Amber Heard.
• Heard mentioned Moss earlier in the trial while recounting why Heard punched him in self-defense.

Johnny Depp's legal team will call upon Kate Moss, the actor's former girlfriend, to testify in his case against Amber Heard on Wednesday, a source close to Depp told Insider.

Moss is expected to give her testimony to jurors through a live video link, where lawyers representing both Depp and Heard will have the opportunity to question her. The New York Post first reported on Monday that Moss would be called to testify.

Heard had brought up Moss in her testimony earlier in the trial while recounting a tussle with Depp atop a flight of stairs. Heard said that Depp was attacking her sister and that she punched Depp.

"I don't hesitate. I don't wait. I instantly think of Kate Moss and the stairs, and I swung at him," Heard said.

Heard appeared to be referring to an unverified rumor that Depp once pushed Moss down the stairs when they were dating, at some point between 1994 and 1997. Moss has never publicly accused Depp of misconduct, and in interviews she has spoken fondly of him.

Moss isn't on the original list of witnesses that Depp intended to call for the trial. But court records reviewed by Insider said Depp reserved the right to call "any witnesses identified" by Heard and "any witness necessary for rebuttal or impeachment."

Benjamin Chew, one of Depp's lawyers, appeared animated when Heard mentioned Moss in her testimony. A source close to Depp previously told Insider that Heard's mention of Moss was among an "embarrassment of riches" for Depp's lawyers to cross-examine her and present their rebuttal.

It's not clear whether Heard's attorneys will object to Moss being called as a witness. Before the trial began the parties fought over which witnesses would be permitted to testify, and experts previously told Insider that Heard's passing mention of Moss may not meet the legal thresholds to call her as a witness.

Judge Penney Azcarate, who is overseeing the case in Fairfax County Court in Virginia, has put all the legal filings submitted during the trial under seal, so it's possible that the parties have fought over the admissibility of Moss in filings that remain out of the public eye. A representative for Heard didn't immediately respond to Insider's request for comment.

The trial is over a case Depp brought against Heard alleging that she defamed him by publishing a 2018 Washington Post op-ed article where she described herself as a victim of domestic violence. Though Heard didn't name Depp in the article, Depp alleges it was clear to any reasonable reader that it was a reference to their relationship, which ended in 2016.

Other former partners of Depp, including Vanessa Paradis and Winona Ryder, have publicly supported him. But Ellen Barkin, who dated Depp in 1994, testified in a deposition on Heard's behalf, which was played for jurors at the trial, that Depp had a "jealous" and "controlling" streak and once threw a wine bottle in her direction.

Heard has denied Depp's claims and has recounted about a dozen specific instances of physical violence, which she says often occurred when Depp was under the influence of drugs and alcohol.

Heard is presenting her defense against Depp's defamation case to jurors, as well as her own defamation counterclaim against Depp. When she is finished, Depp's legal team will be able to present his rebuttal and defense of Heard's case.

The blockbuster trial is scheduled to wrap up with closing arguments on Friday before jurors begin deliberating.