Elon Musk Had Twins Last Year with Exec Shivon Zilis Just Weeks Before His & Grimes' Baby Was Born

Elon Musk secretly welcomed twins last year.

The 51-year-old Tesla CEO fathered twins with Shivon Zilis last November, according to court documents published by the Insider Wednesday. The twins were born in Austin, Texas.

The papers reveal that in April, Musk and Zilis –– who is the project director at his Neuralink company –– asked a Texan county court to change their babies' names so they would "have their father's last name and contain their mother's last name as part of their middle name."

The twins' sexes were not made public and their names were redacted from the documents.

An Austin judge granted their request in May, per Insider.

A representative for Musk did not immediately respond to PEOPLE's request for comment. Zilis also did not immediately respond.

The twins' arrival came just weeks before Musk and his former partner Grimes welcomed a baby girl via a surrogate in December, despite the pair splitting up in September. She revealed the birth of Exa Dark Sideræl, who they've nicknamed