Grimes and Elon Musk change son's name from X Æ A-12 to comply with California law

Few baby names have been caused more of a stir than the moniker Grimes and Elon Musk gave to the newest addition to their family.

On May 4, the Canadian singer and technology billionaire welcomed a baby boy, who they later revealed they had called X Æ A-12 Musk.

The unusual choice was widely debated online, as social media users scrambled to attempt to figure out exactly how the name would be pronounced.

Both parents have since taken to social media to clear up the mass confusion, although it seems they each have slightly different ideas.

New mum, Grimes explained X as "the unknown variable" and the choice of Æ to honour the "elven spelling of Ai (love &/or Artificial intelligence)".

She added that "A-12 [is the] precursor to SR-17 (our favourite aircraft). No weapons, no defences, just speed. Great in battle, but non-violent" and said that the A is for Archangel, her "favourite song".

Given Grimes's explanation, baby X Æ A-12's name would be pronounced "Zai-ah", like the name Isaiah without the first syllable.

Musk has since added an interpretation of his own, explaining to podcast presenter Joe Rogan, "it is X, the letter X. The A E [Æ] is pronounced 'Ash' ... and then A-12 is my contribution [for] Archangel-12 the precursor to the SR-71, the coolest plane ever."

"My partner is the one who actually mostly came up with the name," he said. "She is great at names."

However, there has still been one question mark over the newborn’s name. In the state of California, where the family resides, names can only legally be registered with the 26 characters of the alphabet, meaning the choice to include the figure 12 would not comply with the state’s regulations.

And Grimes has now revealed that they have in fact been forced to change their son’s name as a result. On Sunday, the singer replied to a comment on her latest Instagram post in which a fan asked: “Did you change the baby name because of Californian laws? What is the baby's new name?”

“X Æ A-Xii”, Grimes replied, adding: “Roman numerals. Looks better tbh” and “One dash is allowed.”

X Æ A-Xii is the first child for Grimes, while Musk is already father to five sons, Damian, Griffin, Xavier, Saxon and Kai from his first marriage to Justine Wilson. The couple lost their first child, a boy named Nevada, to sudden infant death syndrome (SIDS) in 2000.