Billionaire Elon Musk has weighed in on his ex-girlfriend Amber Heard's legal battle with Johnny Depp, as the jury started deliberations after closing arguments were presented in court. 

The Tesla founder, who allegedly dated Heard while she was married to Depp, tweeted about the Hollywood stars' high-profile trial on Saturday. 

"I hope they both move on. At their best, they are each incredible," he wrote on social media. 

The Tesla and Space X founder was accused by Depp of having a threesome with model Cara Delevingne and Heard in his LA home while he was away filming, a claim the billionaire has denied. 

Musk also became a talking point in the trial when Depp's former agent Christian Carino took the stand. 

Carino, who was formerly engaged to Lady Gaga, was asked if Musk and Heard were dating in 2016. 

"I don't know if they were dating, but they have definitely spent some time together," he said. 

Heard and Musk met on the set of the 2013 Robert Rodriguez film Machete Kills, but the pair claimed they were nothing more than friends until they both finalised their divorces in 2016 and 2017. 

Rumours sparked again in August 2017 that the pair's alleged year-long romance had ended. 

Musk confirmed the speculation shortly after, telling fans the break-up was amicable. 

"Just to clear up some of the press storms this weekend, although Amber and I did break up, we are still friends, remain close and love one another," Musk tweeted. 

He later added that "long-distance relationships when both partners have intense work obligations are always difficult, but who knows what the future holds." 

Fate of trial now in hands of jurors 

Depp's defamation case against Heard is now in the hands of jurors who have started deliberations after hearing explosive closing arguments in court. 

Lawyers for both Depp, 58, and Heard, 36, made their final appeals to the jury on Friday, local time, after dozens of hours of testimony and six weeks of blistering mutual accusations of domestic violence between the celebrity couple in the Fairfax County Court, Virginia. 

Amber Heard and Elon Musk say they began dating after their respective divorces. Photo / Supplied 

Depp's lawyer Camille Vasquez landed one final savage blow by claiming the Aquaman actress had no friends. 

"You may have noticed that no one showed up for Heard in this courtroom other than her sister," Vasquez said. 

"Every other witness who travelled to Virginia for her was a paid expert. 

"This is a woman who burns bridges. Her close friends don't show up for her." 

Vasquez then delivered another brutal swipe at Heard, responding to her lawyers' claims that all of Depp's witnesses who testified in the case were "on his payroll" and too afraid to go against him. 

"Kate Moss is most definitely not on Mr Depp's payroll," Vasquez said, referencing the British supermodel's explosive testimony this week dispelling a rumour Depp pushed her down a flight of stairs. 

Depp's team painted him as a victim of what they say are Heard's false allegations of physical, sexual and psychological abuse, that have destroyed his career and reputation. 

They claim Heard is a "deeply troubled person" who sought revenge when Depp triggered her deepest "fear of abandonment" and "split" during arguments. 

Heard's team delivers final words 

In sharp contrast, Heard's lawyer Benjamin Rottenborn called Depp "a monster" who not only abused his ex-wife, but continued an ongoing smear campaign after Heard filed for divorce. "In Mr Depp's world, you don't leave Mr Depp," he said. "If you do, he will start a campaign of global humiliation against you." 

Vasquez delivered her closing argument first, telling the jury that Heard had "spun a story of horror" based on "wild, over-the-top and implausible" allegations of physical and sexual abuse against Depp. 

"You either believe all of it or none of it," Vasquez told the jury on Friday morning. 

"Either Ms Heard was sexually assaulted (by Depp) with a bottle in Australia … or she's a woman who is willing to say absolutely anything. 

"What Ms Heard testified to in this courtroom is a story of far too many women, but what the weight of evidence shows, is that it's not Ms Heard's story." 

Vasquez described Heard's allegations as "false" and "defamatory", adding that they have caused "irreparable harm" to Depp and "ruined his life". 

She blasted Heard for her "performance" in court, claiming the starlet used her acting experience to play "the role of her lifetime as a heroic survivor of brutal abuse." 

Vasquez told jurors that during the six-week trial, they have seen Heard "sobbing without tears while spinning elaborate, exaggerated, fantastical" claims of domestic abuse. 

"It was a performance," she added. 

"She told you what she thinks you need to hear to convict this man as a domestic abuser and a rapist." 

The lawyer argued that the evidence presented by Heard's legal team "does not bear out" that the actress had been abused "countless times," including the fact that there are no medical records documenting her supposed injuries. 

"There is nothing," Vasquez said.