Musician Grimes (real name Claire Boucher) and entrepreneur Elon Musk have quietly welcomed a second child into the world and their name is every bit as unusual as you might expect.

Speaking in a new interview with Vanity Fair, Grimes revealed that the pair had welcomed their baby – a girl – via surrogate in December and that the unique name they opted for is 'Exa Dark Sideræl Musk', but that they've been calling the little one 'Y' for short. She joins their son, X Æ A-12 (pronounced 'X AI Archangel', who has been nicknamed 'X').

The news of the new addition to the family broke when Grimes was mid-interview and the journalist heard crying in the background. After questioning if there was a new baby on the scene, Grimes initially said she's not "at liberty to speak on these things" but later shared the news and the child's unusual moniker.

"Whatever is going on with family stuff, I just feel like kids need to stay out of it, and X is just out there," she said at first. "I mean, I think E is really seeing him as a protégé and bringing him to everything and stuff.… X is out there. His situation is like that. But, yeah, I don’t know."

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She then went on to say her daughter's name is "fire" – Exa being a reference to the supercomputing term 'exaFLOPS' and Dark representing the 'unknown'. Sideræl is said to be pronounced 'sigh-deer-ee-el', with elven nods.

Previously, Grimes has spoken about raising her offspring as gender neutral, saying, "I don’t want to say the gender of the baby... I feel like their privacy should be protected... I don’t think they can consent to being famous or being in public. I don’t want to gender them in case that’s not how they feel in their life. I don’t know, I just feel like it doesn’t need to be known."

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However, in the new interview she clearly uses he/she pronouns multiple times [so we've done the same too when writing this article].

In the chat, Grimes also commented on her and Elon's relationship, adding, "I would probably refer to him as my boyfriend, but we’re very fluid. 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."

Congratulations on your new bundle of joy, Grimes and Elon!

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Jennifer Savin
Features Editor

 Jennifer Savin is Cosmopolitan UK's multiple award-winning Features Editor, who was crowned Digital Journalist of the Year for her work tackling the issues most important to young women. She regularly covers breaking news, cultural trends, health, the royals and more, using her esteemed connections to access the best experts along the way. She's grilled everyone from high-profile politicians to A-list celebrities, and has sensitively interviewed hundreds of people about their real life stories. In addition to this, Jennifer is widely known for her own undercover investigations and campaign work, which includes successfully petitioning the government for change around topics like abortion rights and image-based sexual abuse. Jennifer is also a published author, documentary consultant (helping to create BBC’s Deepfake Porn: Could You Be Next?) and a patron for Y.E.S. (a youth services charity). Alongside Cosmopolitan, Jennifer has written for The Times, Women’s Health, ELLE and numerous other publications, appeared on podcasts, and spoken on (and hosted) panels for the Women of the World Festival, the University of Manchester and more. In her spare time, Jennifer is a big fan of lipstick, leopard print and over-ordering at dinner. Follow Jennifer on Instagram, X or LinkedIn.