Elon Musk had twins in 2021 with his top executive

Musk and Zilis had in April filed a petition to change the twins' names in order to "have their father's last name and contain their mother's last name as part of their middle name," the Business Insider cited the documents as stating

The order was okayed by a judge in Austin, Texas this May.

The twins were born just weeks before Musk and Claire Boucher, musician who performs as Grimes, had their second child through surrogacy in December.

While Musk has his primary residence, a $50,000 modular house in Boca Chica, near SpaceX's launch facility in South Texas, in the court documents Musk and Zilis listed the same address — the multimillion-dollar home — in Austin, Business Insider reported.

With this, the Space X chief has nine known children.

However, Musk has not commented on the latest revelation.

Earlier, Musk's first wife, author Justine Musk, had told his biographer that he "wanted to get married and have kids early on."

In 2004, the couple had twins Vivian and Giffin and triplets in 2006.

In 2020, he had a child, who was named X Æ A-Xii Musk that was later changed to comply with California law, with his partner Grimes.

In March, the existence of their another child, Exa Dark Sideræl Musk, was revealed.

In 2021, replying to a tweet praising him for his large family, Musk said, "I'm trying to set a good example! Population collapse is a much bigger problem than people realize and that's just for Earth. Mars has a great need for people, seeing as population is currently zero."