Celebrity Parents Grimes Reveals New Name of Daughter with Elon Musk, Shares Rare Photo of the 15-Month-Old Grimes and Elon Musk welcomed a daughter in December 2021 By Angela Andaloro Angela Andaloro Twitter Angela Andaloro is a Parents News Writer at PEOPLE. Angela has also written about entertainment and parenting at LittleThings, Mom.com, BuzzFeed, and more. In her spare time, she enjoys competing in fantasy sports leagues and watching too much reality TV. People Editorial Guidelines Published on March 27, 2023 01:59 PM Share Tweet Pin Email Grimes is sharing a new update on her little girl. The singer and mom of two — who shares daughter Exa Dark Sideræl, 15 months, and son X Æ A-12, 2½, with ex Elon Musk — shared new side-by-side photos of her and her toddler on Twitter Thursday. Both mom and daughter were dressed in red onesies in the photo, with Grimes (born Claire Boucher), 31, sporting green tips at the end of her yellow-blonde hair and the toddler donning a similar look in her little tufts of hair. "Normally we [don't] post her for her privacy, but she's fairly unrecognizable here since shes channeling Goku or smthn," she tweeted as a follow-up to the photo set. Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories. Grimes/twitter, Justin Sullivan/Getty, Grimes/twitter Elon Musk on Relationship with Daughter Who Legally Changed Her Last Name: 'Can't Win Them All' In another tweet, she commented on her toddler's name, writing, "She's Y now, or 'Why?' or just '?'" calling the name "curiosity, the eternal question, .. and such." Grimes also acknowledged that the change isn't official because the "government won't recognize that." In September, Grimes shared photos of her daughter listening to music and playing with a copy of The Birth of Tragedy by German philosopher Friedrich Nietzsche. "My daughter is dancing to techno over this copy of the birth of tragedy by Nietzsche - what a queen," she tweeted alongside the shot of the then-9-month-old leaning on a bench in a black onesie with a pink bow headband in her blonde hair. Grimes first told Vanity Fair that she and Musk welcomed a daughter in December 2021 via surrogate in a cover story for the magazine's April 2022 issue. The singer explained her daughter's unique name to the outlet, telling Vanity Fair that Exa refers to a supercomputing term, exaFLOPS, while Dark represents "the unknown." She explained, "People fear it but truly it's the absence of photons. Dark matter is the beautiful mystery of our universe." twitter At the time, she told the outlet that they plan to have more children too: "We've always wanted at least three or four." In addition to his two children with Grimes, Musk shares 19-year-old twins Vivian Jenna Wilson and Griffin Musk, along with triplets Kai, Damian, and Sax Musk, who were born in 2006, with his first wife, Justine Wilson. The two had another son, Nevada Musk, who died at 10 weeks.