With Grimes and Elon Musk, always expect the unexpected. Not only are the pair back together, but they also... have a secret baby, who was revealed during an interview with Vanity Fair. Yep, it's almost as wild as when they called their first child X Æ A-12.
Predictably, their second child also has a unique name, and their daughter is called Exa Dark Sideræl. Or Y for short. (They call their first son X, too.) Grimes - who suffered with health problems during her first pregnancy - welcomed her second child by surrogate.
The news of their new addition is also surprising as the pair reportedly split up six months ago, but Grimes says they're happier than ever now their relationship is more 'free'. 'I would probably refer to him as my boyfriend, but we’re very fluid,' she said. 'We live in separate houses. We’re best friends. We see each other all the time…. We just have our own thing going on, and I don’t expect other people to understand it. This is the best it’s ever been.... We just need to be free.'
So, what does the name Exa Dark Sideræl mean? Well, according to Grimes, Exa is a reference to 'the supercomputing term exaFLOPS, which is 'the ability to perform one quintillion floating-point operations per second'. The middle name, Dark, is a nod to the 'unknown.' And as for Sideræl - pronounced sigh-deer-ee-el - that's the 'more elven spelling' of sidereal, which Grimes says is 'the true time of the universe, star time, deep space time, not our relative earth time'.
The singer also said that the couple are hoping to have more children, and that X and Y live between their parents' homes. It's the couple's second child, but Musk has five children with his first wife, the Canadian author Justine Wilson. (Wilson and Musk also sadly lost a baby to sudden infant death syndrome in 2002.)