Elon Musk's partner Grimes reveals meaning behind baby name X Æ A-12

Grimes has confirmed she and boyfriend Elon Musk have called their newborn son X Æ A-12 Musk.

Musk confused fans when he first revealed his new son's name yesterday, shortly after announcing the birth.

Reddit fans speculated the name could mean Ash or Sasha, but now Grimes has broken down its full meaning in a tweet.

"X, the unknown variable," she wrote, "Æ, my elven spelling of Ai (love &/or Artificial intelligence)."

"A-12 = precursor to SR-17 (our favorite aircraft). No weapons, no defenses, just speed. Great in battle, but non-violent."

She added that the "A" in the name, as some fans previously predicted, also stands for "Archangel" — which she said is her "favorite song."

As 2020 is the Chinese year of the rat, "12" is the sign's number. So all very simple.

But it turns out even little X Æ A-12 Musk's mother got one detail wrong, as Musk pointed out to her on Twitter. "SR-71, but yes" he wrote about the name of the aircraft.

In response to Musk, she defended her mistake and said that she was "recovering from surgery."

She tweeted him back, "I am recovering from surgery and barely alive so may my typos b forgiven but, damnit. That was meant to be profound."

Grimes first revealed her pregnancy in January, confirming the father was Elon Musk in an interview with Rolling Stone.

The 32-year-old singer has been dating the Tesla founder for two years.