Amber Heard’s lawyers are seeking a mistrial in her multi-million defamation battle with ex-husband Johnny Depp, alleging that a person who was not called for jury service served as a juror in the case.

In documents filed on Friday, Heard’s lawyers cited “newly discovered facts and information” regarding one of the 15 jurors in Fairfax, Virginia – who in June unanimously decided that she had defamed Mr Depp in a newspaper op-ed about domestic abuse and left her on the hook for $8.35 million in damages.

Her lawyers contend that two people with the same name live at the address to which a summons was sent: a 77-year-old and a 52-year-old.

The older of the two formally was summoned to serve on the jury, the filings claim, but instead it was the younger of the two who turned up for jury service.

Elaine Bredehoft, lawyer for the Aquaman star, contended: “The information on the jury panel list appears to be inconsistent with the identity and demographics of one of the jurors.

“Juror No 15 was apparently born in 1970, not 1945, as reported to and relied upon by the parties – including Ms Heard – in selecting a jury panel.

“As the Court no doubt agrees, it is deeply troubling for an individual not summoned for jury duty nonetheless appear for jury duty and serve on a jury, especially in a case such as this.”

The filing contends that Heard’s due process was compromised and that a mistrial should be declared.

“Heard claims it is up to the court to ensure that potential jurors are properly vetted”, Anne Bremner, US attorney and legal analyst told i.

“(But) Depp is arguing that Heard had an obligation to discover this error during jury selection.”

Friday’s filing goes on to state that Virginia puts in place safeguards to avoid these mix-ups from occurring in the first place. It includes the use of a 7-digit juror number, zip code, and birthdate to verify the jurors’ identities.

The filing continues: “When these safeguards are circumvented or not followed, as appears to be the case here, the right to a jury trial and due process are undermined and compromised.”

Ms Bremner highlighted the trial of convicted sex trafficker Ghislaine Maxwell as precedent for high-profile jury identity mishaps – where it was later revealed that one of the jurors failed to disclose he had been sexually abused as a child.

She said: “Absent evidence of prejudice or that this was a stealth juror, it appears that this error was understandable, arguably could have been discovered by the defence, and probably won’t allow Heard to receive a mistrial and new trial.”

Previous filings from Heard’s team claim the decision in favour of Depp was not supported by evidence presented during the six-week trial.

Depp, 59, sued his former partner over a 2018 Washington Post op-ed where she identified herself as a survivor of domestic abuse. His lawyers said that the claims led to the destruction of his film career. Depp told the court that it was in fact he who was abused by Heard – though she was partially successful in a counter-claim over suggestions from his representatives that she had perpetrated a “hoax”.