Kennedy met Heard at a dinner party in the north London home of the novelist Kathy Lette during the trial.
Depp is due to reprise his role as Gellert Grindelwald in the third Fantastic Beasts film, which co-stars Eddie Redmayne.
Heard was subjected to death threats and misogynistic attacks on social media during the libel trial that left her feeling “down and beleaguered”, according to Helena Kennedy QC, who met Heard while the case was before the high court.
There’s no doubt that Amber Heard did … resist but that does not make her certifiable.”