While the baby name announcement sent Twitter into a frenzy as fans tried to figure out if Musk was joking and, if not, how the baby's name is pronounced, Grimes stepped in to explain how they came up with the truly unique moniker in the first place.
Seemingly confirming that their child's name is in fact X Æ A-12, Grimes said each portion and character had a special significance.
According to Grimes, 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."
She went on to explain that the A also refers to "Archangel, my favorite song."
However, when it comes to how to actually pronounce the name, Grimes offered no suggestions. That being said, one fan suggested that the name could be pronounced "X Ash Archangel" -- as Æ is a typographical character referred to as ash.
Musk liked this particular tweet, leading many to think that could be a confirmation.
On Tuesday, Musk also shared a heartwarming update about the couple's bundle of joy when one Twitter user asked if there was any "news on [the] baby?"
"Happy, healthy & cute as a button :)" Musk replied.
The Tesla founder also shared an image of him holding his son in the hospital Monday, after the birth announcement.
In the sweet photo, Musk, who is wearing an "Occupy Mars" T-shirt, cradles X Æ A-12, who's yawning while swaddled in a blanket.
Musk announced the birth of his son on Monday, writing that "mom and baby all good" on Twitter. The news came just four hours after he said that Grimes, whose real name is Claire Boucher, was just "a few hours away" from giving birth.
The couple, who have been dating since 2018, first announced the pregnancy in January. While this is Grimes' first child, Musk shares five kids with his first wife, Canadian author Justine Wilson.