Elon Musk's relationship with Grimes has taken another twist as it has been revealed that the pair became parents to their third child last year.

The Tesla/X boss's relationship with the Canadian musician made headlines when they first went public back in 2018, and their decision to name their first child (born in 2020) X Æ A-Xii proved controversial after Californian law forbade his originally intended name of X Æ A-12. Their eldest son is known as 'X'.

In 2021, the couple welcomed a daughter via a surrogate and named her Exa Dark Sideræl (whose nickname is 'Y'), and now it has been confirmed that they have also welcomed another son, with the equally unusual name of Tau Techno Mechanicus.

Their relationship status, however, is less clear as Grimes previously referred to their relationship as 'fluid' in early 2022, before confirming that they had split later that year. She nevertheless referred to him as "my best friend and the love of my life."

The new addition brings Musk's total number of children to 11, although his first child sadly died of SIDS at 10 weeks old in 2002.

The reason, meanwhile, for the revelation about their third child is due to the publication of a new biography on Musk by Walter Isaacson, due to be released tomorrow.