Elon Musk and Grimes Reveal Why They Named their Baby X Æ A-12

UPDATE: On Tuesday evening, Grimes explained the meaning of the name X Æ A-12, tweeting that X stands for "the unknown variable," while Æ is "my elven spelling of Ai (love &/or Artificial intelligence), while the A-12 refers to an aircraft which is the "precursor to SR-17 (our favorite aircraft). No weapons, no defenses, just speed. Great in battle, but non-violent." Musk had just one correction: "SR-71, but yes."

After a truly unparalleled pregnancy announcement, Grimes and Elon Musk have welcomed their first child together, a baby boy named X Æ A-12.

In a series of tweets and replies to followers on Monday evening, Musk said their child was “A few hours away!,” and later said, “Mom & baby all good.” He also replied to someone asking about the baby's name is "X Æ A-12 Musk." It's unclear whether or not this is a joke, but followers already have theories on the name — chiefly, that it's inspired by an aircraft, which would be on-brand for Musk.

Musk has also tweeted a photo of the baby with a face-tattoo and eyelash filter, and shared another photo of him holding the baby.

The newborn baby is Grimes’ first child, and joins Musk’s five sons from his previous marriage to ex-wife, author Justine Wilson.

And, of course, the baby's name is already inspired some creative Twitter jokes.

Meanwhile, we'll be waiting on either Musk or Grimes to give us a guide on pronouncing "X Æ A-12."