The Tesla founder responded on Twitter after the Wall Street Journal reported on Sunday, that Musk, 51, was involved in a "brief affair" with Nicole Shanahan last fall and cited people familiar with the matter.
The outlet reported that Musk and Brin were previously longtime friends, with Brin even giving Musk $500,000 for Tesla during the 2008 financial crisis. Musk has said over the years that he "regularly crashed" at Brin's home in Silicon Valley, the WSJ also reported.
However, the publication's sources reportedly said that there has been increasing tension between the two moguls and their teams following the alleged "liaison" in December 2021, with Brin requesting that his financial advisers sell his personal investments in Musk's companies.
Representatives for Musk, Brin and Shanahan did not immediately respond to PEOPLE's requests for comment and did not comment to the WSJ.
ANGELA WEISS/AFP via Getty; Image Press Agency/NurPhoto/Shutterstock Elon Musk; Sergey Brin and Nicole Shanahan
Musk replied to a Twitter user who shared the WSJ article with a caption stating that Musk "allegedly banged Google co-founder Sergey Brin's wife leading to the couple's divorce filing" and that "the two are apparently no longer friends."
"This is total bs. Sergey and I are friends and were at a party together last night!" Musk hit back in a post on Twitter Sunday night. "I've only seen Nicole twice in three years, both times with many other people around. Nothing romantic."
Ringo H W Chiu/AP/Shutterstock; Arturo Holmes/FilmMagic
Musk added elsewhere in the thread: "Haven't even had sex in ages (sigh)."
Brin filed for a dissolution of marriage from Shanahan back in early January, according to court documents obtained by PEOPLE.
Together the pair share a young daughter. Brin was previously married to 23andMe co-founder Anne Wojcicki from 2007 to 2015, and they share son Benji, 13, and daughter Chloe, 11.
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Brin cited "irreconcilable differences" in his separation from Shanahan, Business Insider first reported, noting that the pair owned joint assets but how they were to be divided was "to be determined."
Additionally, Brin asked for joint custody of their daughter. He also said that he is not seeking spousal support from Shanahan and requested she not be awarded it either.
Brin and Shanahan enlisted a private "temporary judge" to preside over the case, according to Business Insider.
Brin filed in Santa Clara Superior Court as California deals with a backlogged system. The private temporary judge will allow the couple to expedite their divorce despite the backlogged courts. It also ensures a higher level of privacy.
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"Petitioner is a co-founder of Google and one of the wealthiest and most famous technology entrepreneurs in the world. Because of the high-profile nature of their relationship, there is likely to be significant public interest in their dissolution and child custody issues," Brin's attorney wrote in a filing, adding: "Of great concern is that such publicity puts their minor child at risk of danger, harassment, and even kidnapping, if the specifics of their day-to-day whereabouts are exposed to the public."
The Russian-American internet entrepreneur co-founded Google with Larry Page in 1998, and although they both stepped down from their executive positions with the search engine's holding company Alphabet in 2019, Brin still retains a controlling stake, according to Forbes.