Elon Musk got into a Twitter spat with former NASA astronaut Scott Kelly on Sunday after the billionaire entrepreneur appeared to take another high-profile swipe at the LGBTQ community's use of gender pronouns.

"My pronouns are Prosecute/Fauci," Musk, who took control of Twitter in October, wrote, referring to chief White House medical adviser Dr. Anthony Fauci.

Musk’s tweet quickly went viral, amassing over 1 million likes and 100,000 replies by Monday afternoon.

One of those replies came from Kelly, who has commanded the International Space Station on three expeditions. The retired astronaut, who is also the twin brother of Sen. Mark Kelly, D-Ariz., scolded Musk for his flippant remark.

"Elon, please don’t mock and promote hate toward already marginalized and at-risk-of-violence members of the #LGBTQ+ community. They are real people with real feelings. Furthermore, Dr Fauci is a dedicated public servant whose sole motivation was saving lives," Kelly wrote.

Musk, who in addition to being at the helm of Twitter is also the CEO of SpaceX and Tesla, doubled down in his response Kelly.

"I strongly disagree. Forcing your pronouns upon others when they didn’t ask, and implicitly ostracizing those who don’t, is neither good nor kind to anyone," Musk wrote, in part.

In an email to NBC News, Kelly said he felt obligated to speak out against Musk because the matter is "personal" to him, adding that he sees "the pain the hate causes" his gay and transgender family members.

"Sometimes people call me Mark, I feel obligated to correct them," he said, referring to his identical twin brother. "If people referred to me as she/her I would feel obligated to correct them as well."

Twitter Blue launches amid controversial Musk tweets

Dec. 13, 202206:04

Regarding Dr. Fauci, Kelly said he believes the public health official — who was the head scientist leading the country through most of the Covid-19 pandemic and has become demonized by the GOP — did "what he thought was right to protect lives. "

"As a science minded person I feel obligated to defend science," he added.

A representative for Twitter did not immediately respond to a request for comment.

Sunday's Twitter spat was not the first time Musk, who has a transgender daughter, has commented on LGBTQ issues and drawn criticism, particularly regarding the use of pronouns that do not align with an individual's sex assigned at birth.

In July 2020, the billionaire made his views known about pronoun usage, tweeting: "Pronouns suck." Later that year, he elaborated on his views, writing: “I absolutely support trans, but all these pronouns are an esthetic nightmare.”

In a since-deleted tweet — and just several days after his high-profile takeover of the social media giant — Musk shared link to an unfounded anti-LGBTQ conspiracy theory about the attack on House Speaker Nancy Pelosi's husband, Paul Pelosi. The conspiracy theory suggested, with no evidence, that Pelosi's assailant was actually a “male nudist hippie prostitute.”

Musk's controversial tweets on Sunday come amid a seemingly endless stream of headlines the billionaire has generated since he took over Twitter.

Just days after formally taking over the company, he abruptly laid off a significant proportion of his employees, sending shock waves throughout the tech industry.

And in late November, Musk reinstated former President Donald Trump to the site, almost two years after the company banned him citing his role in the Jan. 6 insurrection at the U.S. Capitol. The billionaire CEO also reinstated other previously suspended accounts, including those belonging to conservative firebrand Rep. Marjorie Taylor Greene, R-Ga., and anti-trans pundit Meghan Murphy.

The company also recently announced it is "no longer enforcing the Covid-19 misleading information policy."

While Musk has repeatedly maintained that the company has not altered any of its moderation policies regarding hate speech, the uncertainty over what the platform will look like under his leadership has prompted some of Twitter's advertisers to pull back on purchasing promotional placements on the site.