In a text message to Paul Bettany, Johnny Depp discussed killing Amber Heard, writing that he'd "drown her before we burn her"

While being cross-examined by Amber Heard's legal team, Johnny Depp testified about doing recreational drugs with famous friends like Marilyn Manson and Paul Bettany.

On Thursday, Depp's past text messages were presented as evidence, showing the actor referring to his substance abuse and alcohol addiction as his "monster." Heard's lawyer Ben Rottenborn showed message exchanges between WandaVision actor Bettany, 50, including one in which the two once joked about killing Heard.

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When asked by Rottenborn if Bettany was a "good friend you've done drugs with," Depp confirmed "yes" after noting, "That's a strange question. Paul Bettany is a good friend, yes."

The pair — who co-starred in the the movies The Tourist (2010), Transcendence (2014) and Mortdecai (2015) — did drugs together "at times," Depp added.

Texts from June 2013 showed the two joking about how to murder Heard, with Depp writing, "Let's drown her before we burn her!!! I will f--- her her burnt corpse afterwards to make sure she is dead." Bettany replied, "My thoughts entirely! Lets be CERTAIN before we pronounce her a witch."

Reps for Bettany didn't immediately respond to PEOPLE's request for comment.

Actor Johnny Depp stands in the courtroom at the Fairfax County Circuit Court in Fairfax, Va., . Actor Johnny Depp sued his ex-wife Amber Heard for libel in Fairfax County Circuit Court after she wrote an op-ed piece in The Washington Post in 2018 referring to herself as a "public figure representing domestic abuse Credit: Jim Lo Scalzo/AP/Shutterstock

Later, when asked if he has done drugs like cocaine with musician Manson, Depp, 58, said, "We've had cocaine together maybe a couple of times," and joked, "I once gave Marilyn Manson a pill so that he would stop talking so much."

In his witness testimony earlier this week, Depp admitted seeing his past messages was embarrassing and explained that when writing he sometimes uses "dark humor" to express himself.

Bettany has previously expressed that it was "embarrassing" to have his texts made public when they were used in the U.K. libel case Depp brought against The Sun, which he lost. Bettany clarified that he "didn't know Johnny when he was married to" Heard.

Marilyn Manson, Johnny Depp, Paul Bettany Credit: Jo Hale/Redferns via Getty; Jesse Grant/Getty; Dimitrios Kambouris/WireImage

"I knew him before. But we hadn't spoken for years. During the marriage I didn't know them. So I wasn't around for any of that," Bettany added to U.K.'s The Times in February, after saying, "We live in a world without context."

Reps for Manson didn't immediately respond to PEOPLE's request for comment.

Depp is suing Heard for defamation over a 2018 op-ed she wrote for the Washington Post about surviving domestic violence, though she never mentioned Depp by name in the article. Depp originally filed the $50 million lawsuit in March 2019.

Heard has not yet taken the stand in this court case. During opening statements last week, her attorney Rottenborn said evidence will show she suffered domestic abuse by Depp that "took many forms," including physical, emotional, verbal and psychological, as well as "sexual violence at the hands of Depp." A spokesperson for Depp denies the allegation as "fictitious."

When discussing the headline used for the online version of Heard's op-ed, the attorney explained that she did not write that headline herself or get to approve it. It read: "Amber Heard: I spoke up against sexual violence — and faced our culture's wrath. That has to change." However, the attorney claimed Heard has indeed been the victim of sexual violence by Depp.

Actor Johnny Depp listens as he testifies in the courtroom at the Fairfax County Circuit Court in Fairfax, Va., . Actor Johnny Depp sued his ex-wife Amber Heard for libel in Fairfax County Circuit Court after she wrote an op-ed piece in The Washington Post in 2018 referring to herself as a "public figure representing domestic abuse Credit: Jim Lo Scalzo/AP/Shutterstock

About the headline, "tragically, it's true," Rottenborn told the courtroom. "Amber did suffer sexual violence at the hands of Depp. ... You will hear in the most graphic and horrifying terms about the violence that she suffered. You'll hear that straight from her. She will get on the stand and she will tell you that. It happened."

Shortly after, Rottenborn listed a time when Depp allegedly had a three-day, alcohol-fueled blackout while in Australia in 2015 toward the end of their marriage, when Depp "abused and sexually assaulted Amber, all because she had the courage to confront him about his drinking."

Heard and Depp, who met while making the 2011 movie The Rum Diary and wed in 2015, broke up in May 2016, when Heard sought a domestic violence restraining order against him, accusing him of abusing her. Depp denied the claims, and the former couple settled their divorce out of court in August 2016.