The last-minute submission came in the third week of Depp's lawsuit against Britain's tabloid The Sun in London's High Court over a 2018 story accusing him of being a "wife beater".

The Pirates of the Caribbeans franchise actor says the false allegation ruined his reputation and cost him lucrative Hollywood jobs.

The Sun counters it can back up its claim by 14 cases of abuse against the 34-year-old model and actress in a three-year span leading up to Heard's 2016 decision to file for divorce.

Depp's lawyer David Sherborne interrupted planned testimony Friday and asked judge Andrew Nicol to allow him to play what he called "critical" new evidence in the case.

Nicol agreed despite the star-studded case running behind schedule on what was supposed to be its last day.

The undated video showed Amber's sister Whitney chatting with a group of women by a sunny pool.

"Did you get in a fight or something?" one women asks Whitney in the video.

"Oh ha ha thank you. Got into an altercation," Whitney replies with a laugh. "I already talked about it. I won't talk about it any more."

"I can't believe Amber beat your ass," the women tells Whitney with a smile on her face. "I know you can beat her ass."

A woman then appears to inspect Whitney's cheek and arm.

"She really whooped your butt," she tells Whitney.

"Yeah, I'm done. I guess I'm done talking about it," Whitney replies in a more serious tone.

Read also: Johnny Depp and Amber Heard: From romance to rancor

'Bad reality TV'

Depp's lawyer said he received the video after Whitney on Thursday denied that Heard had a temper and regularly attacked her husband.

Sherborne said the tipster understood Whitney was lying and had video proof.

The lawyer added that it showed that Whitney was tailoring her testimony to fit her sister's own account.

"There is no denial of the fact that Ms Amber Heard beat up Whitney Heard and that there are injuries," Depp's lawyer said.

Depp claims that Heard attacked him regularly and he only acted out against her in self defense.

Whitney explained Friday that the video was an outtake of a "really bad reality TV show" in which the cast was trying to make "a very, very boring story more interesting".

"We were referencing a verbal argument my sister and I had got into the night before," she said.

Whitney added that other members of the cast were "looking for injuries that were not there".

The Sun's lawyer Sasha Wass dismissed the video as "flippant, certainly not serious".

"This is a light-hearted exchange, there is no evidence of any injuries and it will take the matter... no further," Wass insisted.

Both legal teams have accused the other sides' witnesses of lying under oath.

Whitney testified Thursday that Heard only hit Depp on one documented occasion and had never been violent toward her or anyone else.

The case is due to finish after legal submissions on Tuesday.