The baby is the pair's second child together. Their son, X Æ A-12, was born in 2020.
Grimes also told Vanity Fair about the meaning of their new daughter's name, saying the first part, "Exa," is a reference to the supercomputing term exaFLOPS. "Dark" represents "the unknown," what Grimes called "the absence of photons, the beautiful mystery of our universe."
Lastly, Sideræl is a "more elven" spelling of the word sidereal, which the singer defines as "the true time of the universe, star time, deep space time, not our relative earth time." Pronounced "sigh-deer-ee-el," Sideræl doubles as a shoutout to Grimes' favorite "Lord of the Rings" character, Galadriel.
Grimes told Vanity Fair that she and Musk were back together but "fluid" after their split in September 2021.
"We live in separate houses. We're best friends. We see each other all the time," Grimes said. "We just have our own thing going on, and I don't expect other people to understand it."
However, Grimes later tweeted that she and Musk have broken up again "since the writing of the article." In the tweet, Grimes said Musk is her best friend and the love of her life.
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