The actor, who appeared alongside Depp in 2012’s Dark Shadows, shared an image to Instagram of the two of them together on the red carpet.
“I have no doubt Johnny will emerge with his good name and wonderful heart revealed to the world, and life will be better than it ever was for him and his family ,” she wrote in the caption.
Other stars who have expressed their support for Depp include his Before Night Falls co-star Javier Bardem, and his Edward Scissorhands co-star and former partner, Winona Ryder.
You can follow the latest updates from the trial here.
Depp is suing Heard for $50m (£38.2m). He alleges that Heard implied that he abused her in a 2018 Washington Post op-ed about domestic violence.
Heard is countersuing for $100m (£80.9m), accusing Depp of orchestrating a “smear campaign” against her and describing his lawsuit as a continuation of “abuse and harassment”.
On Thursday (19 May), before court proceedings began for the day, Depp had greeted cheering supporters outside the courtroom, joking that he had prepared “breakfast for all of them”.
When asked what he had made for them, Depp responded: “Waffles.”
He also slipped into his Captain Jack Sparrow character for fans, telling them: “He’s still around somewhere.”
On Wednesday 18 May, former *NSYNC singer Lance Bass came under fire for mocking Heard’s emotional testimony in a viral TikTok video.