Grimes and Elon Musk’s Christmas present was a new baby. The once-and-apparently-future couple secretly welcomed a second child in December, the 33-year-old accidentally revealed to Vanity Fair in a new cover story published on Thursday. The baby girl, born via surrogate, is named Exa Dark Sideræl, but the new parents call her “Y”, musician Grimes said. Son X Æ A-Xii, born in May 2020, goes by X. It is unclear if they ever intended to reveal their new family member, as Vanity Fair got the scoop only when reporter Devin Gordon heard her crying upstairs during the interview. Thank you so much. @Vanity Fair for putting me on the cover!!!! @DevinGordonX (Thread-ish) 🧝🏻♀️🧬🪐 pic.twitter.com/AMrbBTOKCR — 𝔊𝔯𝔦𝔪𝔢𝔰 (⌛️,⏳) ᚷᚱᛁᛗᛖᛋ (@Grimezsz) March 10, 2022 As for mum and dad, that seems to be a bit more complicated. “There’s no real word for it,” Grimes told Vanity Fair . “I would probably refer to [Musk] 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.” They are happy though, at least. Elon Musk says he and girlfriend Grimes are ‘semi-separated’ “This is the best it’s ever been,” she said. “We just need to be free.” Grimes and Tesla founder Musk went public with their relationship at the Met Gala in 2018, months after the 50-year-old SpaceX founder split from actress Amber Heard. They announced their break-up in September.