JOHNNY Depp's 'heartfelt' apology over dogs Pistol and Boo could go down as one of his worst performances ever.

The Pirates of the Caribbean movie star appears in a 42 second video for the Department of Agriculture to warn people about the need to protect Australia's biodiversity.

LISTEN: Barnaby Joyce says the video proves he was right to take a stand

It came after his wife Amber Heard was charged for failing to declare their pet 'terrorists' when she visited him during his filming on the Gold Coast in Queensland last May.

In contrast to a super-excited former Agriculture Minister Barnaby Joyce, who threatened to have the dogs euthanised, Depp and his wife appeared almost asleep in the video.

The performance has already spawned a parody video where the couple are seen to be reading a script at gunpoint.

Depp slurs his words and is barely comprehensible.

"Australia is a wonderful island that has a treasure trove of unique plants and animals,'' Amber Heard says in the opening of the video, almost smirking at Depp.

"It has to be protected,'' Depp chimes in, on cue.

"Australians are just as unique, both warm and direct,'' Depp explains to potential visitors.

"Disobey Australian law and they will tell you firmly.''

Ms Heard goes on to apologise for failing to tell authorities about their dogs, which they flew into the country on a private jet.

"I'm truly sorry that Pistol and Boo were not declared.''

"Protecting Australia is important.''

"Declare everything,'' Depp adds, nodding before for the video fades to black.

Was it convincing? Hardly.