Grimes and Elon Musk have a third child together, according to a new biography of the oddball billionaire.

The New York Times has reviewed journalist Walter Isaason's eponymous book about the SpaceX and Tesla mogul, which will hit the shelves on Tuesday.

According to the publication the 51-year-old and Grimes, real name is Claire Boucher, have welcomed a son named Techno Mechanicus, who also goes by the moniker “Tau". Musk subsequently confirmed the story and the child's name on a post on his social media platform X, formerly known as Twitter.

The Times does not reveal any more details about the infant, such as when or where he was born.

Musk and Grimes, 35, welcomed son X Æ A-12, whose name was later changed to X Æ A-Xii and is nicknamed “X”, in May 2020. They then had a daughter born via surrogate in December 2021, named Exa Dark Sideræl, who is nicknamed “Y".

In a March 2022 Vanity Fair interview revealing Exa Dark’s birth, Grimes admitted the on-off couple wanted more children, however, the day the article was released she tweeted that they had split up again.