Johnny Depp is asking the court to order American Civil Liberties Union (ACLU) to reveal how much Amber Heard donated from her $7million divorce settlement after she told the court that she gave half of the money to the organisation.

The "Pirates of the Caribbean" star and his legal team believe that the actress lied about the amount during London's High Court trial with The Sun last year. Finding the truth on whether she actually gave half the amount is important as it is the basis of his claim that she only married him for his money.

She told the court then that she has split the $7 million between ACLU and the Children's Hospital in Los Angeles. The judge ruled that Heard's charity donation is "hardly the act one would expect from a gold-digger."

But the hospital has since revealed that it only received $100,000 from her and not the $3.5 million she promised after she finalised her divorce from Depp in August 2016. The actor's lawyers believe the same to be true for ACLU. As such they have subpoenaed the organisation to reveal the exact amount.

In court documents filed in New York and obtained by People, the "Rum Diary" star "respectfully requests that this Court enter an order directing the ACLU Witnesses to fully comply with the Subpoenas," which aims to discover information concerning "any donations to the ACLU Foundation by Ms. Heard or in her name, and/or any public statements related to such donations."

The subpoenas are for the discovery of any "communications with Ms. Heard or those acting on her behalf concerning her relationship with Mr. Depp and divorce from Mr. Depp; discovery concerning Ms. Heard's work as an 'ambassador' for the ACLU Foundation and the conception, drafting, and placement of the Op-Ed; and communications with Ms. Heard or those acting on her behalf concerning the Virginia Action and the preparation and submission of the Wizner Declaration."

Today I published this op-ed in the Washington Post about the women who are channeling their rage about violence and inequality into political strength despite the price of coming forward.

From college campuses to Congress, we're balancing the scales.

— Amber Heard (@realamberheard) December 19, 2018

Heard's team defended the actress saying that she has done "nothing dishonest" and that she has "pledged to pay over 10 years" which ACLU "understood." Her team also presented proof that she gave $950,000 to the group and $850,000 to the Children's Hospital via anonymous donours.

Depp's team believes that Elon Musk paid for Heard in her name and she did not use her own money. If proven true, then the findings will be beneficial in his defamation trial against her in Virginia next year.

Elon Musk and Amber Heard
Elon Musk and Amber Heard split in August 2017 after almost a year of dating Getty