Heard had previously announced that the $7 million she was receiving as part of her divorce settlement with Depp would be donated and split between the American Civil Liberties Union and the Children's Hospital of Los Angeles.
A statement, released Thursday, reads, "Amber Heard appreciates Johnny Depp's novel interest in supporting two of her favorite charities, the ACLU for domestic violence and the Children's Hospital of Los Angeles. This is great and unexpected news."
"However, if Johnny wishes to change the settlement agreement, we must insist that he honor the full amount by donating $14 million to charity, which, after accounting for his tax deduction, is equal to his $7 million payment obligation to Amber. We would also insist that the full amount be paid immediately and not drawn out over many years," it continued.
"Anything less would be a transparent attempt by Johnny's counsel, Laura Wasser and Patti Glaser, to reduce their client's true payment by half under the guise of newfound concern for charities that he has never previously supported."
A rep for the Alice Through the Looking Glass star responded stating, "Following Amber Heard's announcement that her divorce settlement was to be divided equally and gifted to Children's Hospital of Los Angeles and the American Civil Liberties Union, two exceptionally deserving and important charities, Johnny Depp has sent the first of multiple installments of those monies to each charity in the name of Amber Heard, which when completed will honour the full amount of Ms Heard's pledge."
"Ms Heard's generosity in giving to these wonderful causes is deeply respected," it continued.
Recently, Heard and Depp settled outside of court amid the pair's domestic violence case and divorce. As part of the settlement, the Justice League star withdrew her domestic violence case and did so with prejudice, meaning, she cannot re-file in the future. Heard's restraining order against Depp was also lifted.
Days before the agreement, Heard denied leaking a video online of the actor in a fit of rage as he was seen yelling and breaking bottles.
Depp, 53, and Heard, 30, met while starring together in 2011's The Rum Diary and tied the knot in February of 2015. The actress filed for divorce in May, just days after the death of Depp's mother, citing "irreconcilable differences."