The Canadian singer revealed to Vanity Fair she and Musk welcomed another baby in December 2021.
“She’s a little colicky too," Grimes told the outlet for an April 2022 cover story.
Grimes, 33, and the SpaceX founder and Tesla CEO, 50, are already parents to 22-month-old X Æ A-12, whom they call X.
The mom of two, whose name at birth was Claire Elise Boucher, told Vanity Fair their baby daughter is called Y, and was welcomed with the help of a surrogate.
Despite a public split in September 2021, Grimes shared she and Musk have reconnected.
“There’s no real word for it,” she told the outlet. “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.”
The singer also made it clear there will be more babies for the couple.
"We’ve always wanted at least three or four," she said.
Last September, Grimes said she did not identify with the word mother.
“Being a mother feels weird to say," said in a Vogue video. "For some reason, I don’t identify with that word. Which is also really weird, because X, he says Claire, but he doesn’t say Mama."
She continued, “Maybe he can sense my distaste for the word ‘mother.' Which I don’t even know why I have a distaste for it, because I respect ... I just can’t identify with it, weirdly.”