Elon Musk and Grimes secretly welcomed their third child, named Techno Mechanicus.

In a new biography, the internet millionaire and new owner of Twitter - now known as X - is claimed to have welcomed a third kid with electro-pop artist Grimes with another strange moniker.

NCIS' Eric Olsen calls for Deek's return in new spin-off series after LA cancellation

Elon Musk and Grimes have had their third kid, a male named Tau Techno Mecanicus.

His birth has been kept secret until the release of a new biography Elon Musk, 52, on September 12.

Walter Isaacson's book confirms Tau was born in secret, making him Musk's 11th child in total.

Musk and Grimes welcomed their first kid, X A-12, or X, in 2020, followed by Exa Dark Siderael Musk in 2022.

.A review of Isaacson's biography corroborated the news in the New York Times, and Musk has since acknowledged Tau's existence on X/Twitter.

Techno Mechanicus, Circumference/Diameter," he replied on Saturday evening.

Grimes and Musk's relationship has been on and off over the years, and they announced in March 2022 that they have semi-split.

The news of their third kid comes only a few days after Grimes implored Musk to let her "see my son" in a now-deleted post.

Top 5 Zodiac Signs Women Who Always Overreact