Johnny Depp has accused Amber Heard of throwing a "haymaker" punch at him after he turned up to her birthday party in a bad mood because he'd found out he'd lost $650 million.

Depp, 57, returned to the witness stand today for his final round of testimony after four days giving evidence as part of his libel case against News Group Newspapers.

During this morning's session, Depp was asked about an alleged bust-up with Heard on the night of her 30th birthday party on April 21 2016.

The actor told the court he rowed with his wife after he turned up to the bash late and in a bad mood following an "unpleasant and ugly".

He told the court he'd found out he'd lost his entire $650 million fortune and was left $100 million in debt.

Johnny Depp arriving at the High Court in London today

The actor's lawyer, David Sherborne asked: "Can I ask how much?"

Depp replied: "It was put to me this way. It was put to me since Pirates II and III I had made - and it seems a ludicrous number - $650 million.

"When I fired them for the right reasons I had not only lost the $650 million but I was $100 million in the hole because they had not paid the government my taxes for 17 years.

"It was a bad meeting.''

He went on to reveal he smoked a joint on his way to Heard's party to calm himself down.

He then told the court he went to bed to read a book and claims Heard attacked him for ruining her party.

Amber Heard arrived at court today

He said he had withdrawn because he "felt it was the best thing to do" to remove himself from the argument.

He had been "harangued" by Heard after turning up to her party late.

Depp said she attacked him swinging "haymakers". Asked what one was he relied: "It's a bit of a wild swing but effective if it reaches the target.''

However, he denied he'd been violent towards Heard.

Depp finished his testimony and the judge thanked him as he stepped down from the witness box, with the actor joking: "I’m going to miss this".

He spent 25 hours on the stand over the last five days of the trial.

Amber Heard and Johnny Depp pictured in 2015

During this morning's testimony, Depp told the court he had battled deadly bug MRSA after undergoing surgery to reattach his severed finger.

The actor claimed he lost the tip of the digit when Heard threw a vodka bottle at him during a row in Australia in March 2015.

He flew back to LA for surgery, and claims he then caught MRSA.

Depp told the court: "I went back to LA to have surgery - they put a pin in my finger and I ended up catching MRSA, which is quite a painful disease."

He also revealed he'd been left broke after losing his entire $650 million movie fortune and wracking up $100 million in debt.

Depp claimed Heard attacked him after he arrived late to her birthday party

The actor also addressed claims he headbutted Heard in a row on December 15 2015 - the day before she was due to appear on the Late Late Show With James Corden.

Depp insisted his then-wife had attacked him, and claimed blood seen on her mouth by a nurse two days later was caused by Heard picking at her dry lips - not by a headbutt.

Johnny Depp libel trial latest

Depp has denied he was ever violent towards his ex-wife and has accused her of abusing him during their marriage.

Lawyers for NGN are defending their case based on Heard's 14 allegations of abuse, which include claims of bust-ups between 2013 and 2016.

The actor has argued his ex-wife was abusive towards him during the marriage, which collapsed in 2016.

The case continues.