Elon Musk has a third child with former partner Grimes according to a new biography about the Tesla CEO.
Musk and Grimes were first romantically linked to one another back in May 2018.
The pair have since separated but it turns out they share a third child, whose existence has 'been kept private until now' - confirmed in the biography written by Walter Isaacson and reviewed in the New York Times.
Musk and Grimes' third child is reportedly called Techno Mechanicus - or if that's a bit of a mouthful, you can call him Tau for short.
In the review of the biography, New York Times writer Jennifer Szalai says: "The musician Grimes, the mother of three of Musk’s children (the existence of the third, Techno Mechanicus, nicknamed Tau, has been kept private until now), calls [Musk's] roiling anger 'demon mode' - a mind-set that 'causes a lot of chaos.'
"She also insists that it allows him to get stuff done."
Social media users have flocked to X - formerly known as Twitter - to respond to the news of Musk and Grimes' third child being born.
One user wrote: "Not gonna lie, Techno Mechanicus is a banger of a name."
"I have an apostrophe in my name and can’t use half the websites. These poor kids are in for a journey," another added.
And a third said: "Bro wants to make his own Transformers movie at home."
According to the biography, Tau is the tenth child of Musk's - children he shares with three separate women.
Isaacson is said to have gained such an insight into Musk's life by shadowing him for two years with 'unprecedented access' to his life.
The book's publishers, publishers Simon & Schuster, state: "He shadowed Musk, attended his meetings, walked his factories with him and spent hours interviewing him, his family, friends, coworkers and adversaries.
"The result is the revealing inside story, filled with amazing tales of triumphs and turmoil, that addresses the question: are the demons that drive Musk also what it takes to drive innovation and progress?"
Ultimately, the autobiography, simply titled Elon Musk, 'charts Elon Musk’s journey from humble beginnings to one of the wealthiest people on the planet' and asks: 'But is Musk a genius or a jerk?'
Elon Musk is set for release on Tuesday, 12 September.