Elon Musk and Grimes have apparently welcomed their third child together in secret, as disclosed in an upcoming biography about the Tesla CEO. The biography, written by Walter Isaacson and titled "Elon Musk," reveals that the former couple now has a new son named Techno Mechanicus, affectionately nicknamed "Tau." As of now, it's unclear whether the biography, set to release on September 12th, contains more details about the child's birth, such as his age and place of birth.

Elon Musk, aged 52, and Grimes, aged 35, already co-parent two other children: their son X AE A-XII, who is 3 years old, and their daughter Exa Dark Sideræl, who was born via surrogate in December 2021. The couple, who separated in September 2021 after a three-year relationship, maintained an amicable co-parenting relationship.

Musk explained the situation to Page Six, saying, "We are semi-separated but still love each other, see each other frequently, and are on great terms." He attributed the separation to the demands of his work at SpaceX and Tesla, which often required him to be in Texas or traveling internationally, while Grimes' work was primarily in Los Angeles. At the time, Grimes was staying with him, and their child X was in the adjacent room.

 In addition to his three children with Grimes, Elon Musk has six other children from his previous marriage to Justine Wilson.