Elon Musk and Grimes welcomed a new baby into their lives in December last year, the 33-year-old singer revealed in an interview with Vanity Fair published on Thursday.

In the interview with Vanity Fair reporter Devin Gordon, Grimes initially said she was “not at liberty” to discuss whether she and Musk had welcomed a new child, but gave in moments later, saying, “She’s a little colicky too,” when the reporter quizzed her about hearing an infant cry upstairs in Grimes’ home.

The couple’s new child was born of surrogacy and has been named Exa Dark Sideræl Musk, or ‘Y’ for short.

Also read | Exa Dark Sideræl: Elon Musk’s daughter’s name, meaning, and pronunciation

According to Gordon, “Exa is a reference to the supercomputing term exaFLOPS (the ability to perform 1 quintillion floating-point operations per second),” while dark, in Grimes’ words, signifies “the unknown. People fear it but truly it’s the absence of photons. Dark matter is the beautiful mystery of our universe.”

Musk and Grimes had previously taken the internet by storm when they announced that their first baby, born in May 2020, had been named X Æ A-XII, or ‘X’ for short. It seems that the couple have stuck to their love for unorthodox names with Y too.

Yet, the question on everyone’s mind is whether Musk and Grimes are still together, as the SpaceX founder had told the New York Post in September 2021 that they were “semi-separated but still love each other, see each other frequently and are on great terms.”

Also read | SpaceX to focus on cyber defence after Starlink satellites jammed over Ukraine

Grimes shed further light on the status of her relationship with the 50-year-old billionaire during the Vanity Fair interview, saying, “There’s no real word for it. 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. … This is the best it’s ever been. … We just need to be free.”

She went on to say that they would co-parent both X and Y, but pointed out that they were splitting parenting duties. “The best situation here is me training the girl and [Musk] training the boy,” the 33-year-old told Vanity Fair.

Grimes also hinted that she and Musk could have more children in future, and told the publication, “We’ve always wanted at least three or four [children].”