It has been revealed that the Tesla CEO and futuristic-pop singer welcomed their second child last December.

In an interview with Vanity Fair, Grimes - who's real name is Claire Boucher - said that the baby was born via surrogate.

The baby girl is named Exa Dark Sideræl Musk, which rolls off the tongue a bit better than their first child's name. The two welcomed X Æ A-12 back in May 2020, to much confusion over pronunciation, which turns out to be "X A.I. Archangel."

Musk and Grimes split up last year but, when asked about their current relationship, the Canadian singer said, "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."

The couple also plan on having more children. "We've always wanted at least three or four."

After the interview she later tweeted that the couple had broke up once again but that they remained close.

Grimes also tweeted that she wanted to keep her daughter's life "as private as possible."

Exa Dark Sideræl is Grimes' second child and Musk's seventh.