Sister Amber Heard described a brawl in which she said the actress and Johnny Depp hit each other.
Giving evidence in a high-profile defamation trial, Whitney Hurd Enriquez said Hurd shouted at Depp from the mezzanine above the kitchen in March 2015.
Ms. Enriquez said she went to reassure her sister, and described how Depp threw a jar that hit another man in the room before Depp ran “up the stairs.”
Ms. Enriquez said: “I am facing Amber and [Depp] comes up from behind and hits me in the back.
“I heard Amber say, ‘Don’t beat my damn sister.’
She added: “Johnny grabbed Amber by the hair with one hand and hit her in the face several times with the other.”
Giving testimony earlier, Hurd admitted to hitting her ex-husband.
Depp is suing his ex-wife for $ 50 million (£ 40 million), claiming she slandered him when she stated in a newspaper article that she was a victim of domestic violence.
Hurd filed a counterclaim for $ 100 million (£ 81 million), claiming he disgraced her by calling her a liar.
Depp claims that he never beat Hurd and that he was a victim of violence by his ex-wife.
Another witness on Wednesday was Melanie Ingles, who was Hurd’s makeup artist.
She told how she covered up the injuries on the actress ’face for appearing on The Late Late Show with James Corden in December 2015.
“We covered the discoloration, the bruises a little heavier concealer,” Ms. Inglesis said.
Raquel Pennington also testified – she called herself a friend of both Depp and Hurd, but now says she’s gone.
Ms. Pennington said Depp calls his “alternative self” a “monster.”
Ms. Pennington said, “First [of the relationship]I wasn’t worried.
“Towards the end, when the physical bullying was more obvious, I was worried. I worried about her physical safety.
“I was worried that if he turned around, he might do something worse than he ever wanted to.”
Ms. Pennington said she saw Hurd in 2016 with her hair torn from her head, and after a trip to Australia in 2015, Hurd returned with cuts to her legs and arms.
She was also asked to describe a photo of Hurd, taken in December 2015, in which the actress was with broken eyes and a swollen nose.
Asked directly if she had ever seen Depp kick, kick or throw anything at Hurd, the witness said she had not.