The lawsuit is over an opinion piece that Ms Heard wrote for the Washington Post.
In the piece, Ms Heard called herself a victim of violence.
Johnny Depp denies any abuse towards Ms Heard and she has sued back with a $100m counterclaim against the actor.
The civil trial, which is taking place in Virginia, is now in its third week and it is being watched all over the world.
But when does the trial end and how can you watch it online in the UK?
Here's everything you need to know:
Why is Johnny Depp suing Amber Heard?
Mr Depp filed a lawsuit against his ex-wife in 2019 and he alleges that Ms Heard defamed him in an op-ed she wrote for the Washington Post in 2018.
The piece is titled: ‘I spoke up against sexual violence – and faced our culture's wrath. That has to change.’
In the op-ed, Ms Heard wrote: ‘Like many women, I had been harassed and sexually assaulted by the time I was of college age. But I kept quiet — I did not expect filing complaints to bring justice. And I didn’t see myself as a victim.
‘Then two years ago, I became a public figure representing domestic abuse, and I felt the full force of our culture’s wrath for women who speak out.’
The Pirates of the Caribbean actor is not mentioned by name in the op-ed but his lawyers have argued that the piece contains a 'clear implication that Mr Depp is a domestic abuser.’
Mr Depp has asked for compensatory damages of ‘no less than $50m.’
Ms Heard filed a counterclaim against her ex-husband in August 2020 in response to the libel lawsuit.
She accused him of allegedly causing a 'smear campaign' against her and described his lawsuit as 'abuse and harassment'.
Ms Heard has asked for compensatory damages of 'no more than $100m', which is twice the amount that Mr Depp asserted against his ex-wife.
Mr Depp took to the stand yesterday (April 19) to give his testimony.
In the testimony, the actor recounted instances of abuse in his childhood and addressed the alleged abuse against his ex-wife.
He said that the domestic abuse allegations were ‘not based on any truth’.
He added: ‘Nothing of the kind ever happened.
‘Never did I myself reach the point of striking Ms Heard in any way. Nor have I ever struck any woman in my life.’
Mr Depp previously lost a libel battle with News Group Newspapers, which publishes tabloid newspaper, The Sun.
He attempted to sue the organisation for alleged libel over an article that was published in the newspaper in April 2018.
The headline read: ‘Gone Potty: How Can JK Rowling be 'genuinely happy' casting wife-beater Johnny Depp in the new Fantastic Beasts film?’
The trial began in 2020 and Ms Heard testified as a witness for the tabloid newspaper.
Mr Depp lost the libel battle in November 2020 when Justice Andrew Nichol stated that News Group Newspapers proved their allegations were 'substantially true'.
When will Amber Heard take the stand?
Mr Depp’s testimony concluded on Monday, April 25 following a week of intense questioning.
Ms Heard then took to the stand for her testimony and cross-examination, with the cross-examination concluding on Tuesday, May 17.
What did Amber Heard say in her testimony?
Ms Heard’s testimony began on May 4.
The actress held back tears as she spoke about the first time Mr Depp allegedly slapped her.
She said he ‘slapped me across the face’ after she laughed at one of his tattoos as she thought he was making a joke.
Ms Heard added that she had ‘never been hit like that’ before and ‘I knew you don't come back from that, and it broke my heart.’
She also stated that the trial has been ‘the most painful and difficult thing I've gone through’.
What did Amber Heard say during cross-examination?
After Ms Heard testified in court, her cross-examination began.
In the cross-examination, which took place over the space of two days, Ms Heard was questioned about her relationship with James Franco and the abuse accusations against Mr Depp.
She was also questioned on the makeup kit that she used to cover her alleged injuries, whether Mr Depp got her the role in Aquaman and whether she cut her ex-husband’s finger off.
Mr Depp’s attorney, Camille Vasquez, closed her questioning by referencing allegations that Ms Heard hit her ex-girlfriend Tasya van Ree, in 2009.
Ms Vasquez said: ‘Johnny Depp isn’t the only partner of yours that you have assaulted.’
Ms Heard replied: ‘I’ve never assaulted any partner.’
Will Kate Moss testify?
Mr Depp’s ex-girlfriend Kate Moss will testify in the defamation trial.
Ms Moss will attend the trial via video link on Wednesday, according to the New York Post.
The famous model was mentioned earlier in the trial by Ms Heard, where she described a time where Mr Depp allegedly ‘swung’ at her sister.
Ms Heard said it reminded her of another incident during which she alleges that Mr Depp pushed Ms Moss down the stairs when they were dating in the 1990’s.
Ms Moss has not publicly responded to Ms Heard’s claim, however it is possible that she will address the alleged incident when she testifys this week.
When will the Johnny Depp v Amber Heard trial end?
The defamation trial began on Monday, April 11 and it is now in its final week.
How to watch the trial online in the UK
The trial will continue at around 3pm in the UK today (May 18).
It will be available live on Court TV and you can watch or catch up with the trial here.