Moss being called to take the stand was confirmed earlier this week, and she appeared in the court in Fairfax, Virginia, via video link.
The 48-year-old was referenced by Heard, 36, earlier this month during the latter's time on the stand, while discussing an alleged altercation between Depp and Heard's sister, Whitney Henriquez.
The Aquaman 2 actress said Henriquez was near a staircase "in the line of fire … trying to get Johnny to stop," which reminded her of a rumored incident between Moss and Depp, 58.
"[Whitney's] back was to the staircase, and Johnny swings at her," Heard testified. "I don't hesitate, I don't wait — I just, in my head, instantly think of Kate Moss and stairs."
EVELYN HOCKSTEIN/POOL/AFP via Getty; Taylor Hill/Getty; JIM LO SCALZO/POOL/AFP via Getty From left: Johnny Depp, Kate Moss, Amber Heard
Depp's lawyers were spotted fist-pumping when Heard mentioned Moss' name during her testimony, presumably because it gave them the opportunity to bring in the model as an impeachment witness to dispel the rumored incident.
At 5:30 a.m. local time on Sept. 13, 1994, Depp was arrested and charged with criminal mischief at New York's Mark Hotel for allegedly trashing his hotel room.
Police reported they found Depp "in a state of possible intoxication" and Moss uninjured. A criminal-court judge dismissed the charge against Depp on the condition that he stay out of trouble for six months. Depp paid the Mark close to $10,000, including more than $2,000 for damages, plus the bill for the remainder of his reservation.
Moss and Depp called it quits in 1997 after four years of dating and a rumored engagement but later appeared together briefly at the Cannes Film Festival in May 1998.
Heard first made the Moss staircase allegation during her testimony at Depp's U.K. defamation trial in 2020, according to The New York Post.
Depp is currently suing Heard for defamation, arguing that a 2018 op-ed she wrote for The Washington Post about surviving domestic violence tarnished his reputation and ruined his career, even though she didn't mention him by name in the article. He testified that after Heard's allegations against him were made public, he lost "nothing short of everything."
He and Heard married in 2015 and split in May 2016, when Heard sought a domestic violence restraining order against him, accusing him of abusing her. Depp denied the claims, and the former couple settled their divorce out of court in August 2016.
Depp, who has said multiple times under oath that he has never struck Heard or any woman, has testified that his "goal is the truth" as he seeks to clear his name in the trial, which is nearing its conclusion.
If you are experiencing domestic violence, call the National Domestic Violence Hotline at 1-800-799-7233, or go to thehotline.org. All calls are toll-free and confidential. The hotline is available 24/7 in more than 170 languages.