"They have been friends for four years, and they remain just friends now," a source tells PEOPLE of Amber Heard and Elon Musk

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Elon Musk has been seeking a relationship with Amber Heard for years, but a source says his interests have always been strictly platonic.

A source confirms to PEOPLE a Hollywood Reporter report saying that Musk – who had recently been spotted spending time with Heard amid her divorce from Johnny Depp – first took an interest in Heard when he made a cameo in Robert Rodriguez’s 2013 film Machete Kills, in which Heard had a role.

While they didn’t have a scene together, sources close to the set tell the news outlet that Musk began sending emails to Rodriguez and others asking for an introduction.

“If there is a party or event with Amber, I’d be interested in meeting her just out of curiosity,” Musk wrote, according to a snippet of the email obtained by THR. “Allegedly, she is a fan of George Orwell and Ayn Rand … most unusual.”

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According to the report, a dinner was set up, but Heard, who was dating Depp at the time, failed to show up.

“Can you send her a note saying I would like to get together for lunch in LA?” Musk reportedly wrote after the failed dinner, according to THR. “Am not angling for a date. I know she’s in a long-term relationship, but … Amber just seems like an interesting person to meet.”

A source tells PEOPLE that the email exchange did happen, and says Musk often likes to meet “interesting people from all different industries.”

The source adds, “They have been friends for four years, and they remain just friends now.”

Since filing for divorce from Johnny Depp (the two recently reached a settlement), Heard has been spotted spending time with the Tesla founder and tech billionaire, who is in the midst of his own divorce. They were first seen together in Miami, where they were both staying at the Delano South Beach in July. Two weeks later they were again spotted together at a London night club.