Amber Heard felt she was "above the law", her former personal assistant has alleged.
Kate James, who was fired by the actress in February 2015, claimed Ms Heard "did not care about throwing anyone under the bus, if it meant saving her own skin".
In her first witness statement, submitted to the court in Johnny Depp's libel action against The Sun newspaper, Ms James said she had been asked by Ms Heard in September 2014 to send a letter the actress had drafted to Homeland Security officials in the US about a woman named Savannah McMillan.
She claimed Ms Heard, 34, had hired the woman to work as a set assistant.
Ms James said in her written statement: "Savannah, a British citizen, had been held in immigration and questioned about the frequency that she had been coming and going from the USA.
"In Amber's letter, she called it fraudulent that it was being alleged that Savannah was working for Amber unlawfully.
"She (Ms Heard) said that, as Savannah's 'friend', she could 'say truthfully and unequivocally that this allegation is entirely false ... I would like to go on the record saying that Savannah McMillan is a personal friend, and to my knowledge, has never worked unlawfully or otherwise in the United States. Or for me."
Ms James alleged in her statement that she "knew this to be untrue" and "Amber was therefore wilfully lying to the US immigration department".
She added that she took a photo of the letter and a pay cheque from Ms Heard to Ms McMillan.
Her statement also referred to the episode when Ms Heard faced criminal proceedings over her dogs entering Australia illegally.
She claimed she had attempted to talk to Ms Heard about a date discrepancy in the time needed for the dogs' immigration process, but said the actress's eyes "would glaze over and she would walk away".
Ms James alleged Ms Heard "chose to ignore" her and Mr Depp's then estate manager, Kevin Murphy.
"She deliberately smuggled the dogs into Australia," Ms James said in her statement, adding: "As in several circumstances which I observed, it was as if she felt that she was above the law."
Ms James said she had been told about a discussion in which the actress is alleged to have considered asking Mr Murphy to ask her to sign a statement supporting Ms Heard's position that "she (Ms Heard) did not know the dogs were not ready to be taken into Australia".
The witness statement said: "The fact that she was willing to ask me to sign such a statement under oath... is a reflection of her approach to me... in general.
"She did not care about throwing anyone under the bus, if it meant saving her own skin."