Elon Musk and Grimes have added a classic twist to their son’s very modern name.

The Canadian singer and billionaire entrepreneur welcomed their first child earlier this month, naming him X Æ A-12.

However, that name has now been tweaked to X Æ A-Xii.

Grimes, whose real name is Claire Boucher, revealed the adjustment on Instagram after a fan asked: “Did you change the baby name because of Californian laws? What is the baby’s new name?”

She responded simply: “X Æ A-Xii.”

Another follower wrote: “Nice! Just removed the numbers to conform to California law.”

The addition of Roman numerals in place of the final digits is understood to be a way of getting around the Californian law, which forbids the inclusion of numbers in a legal name.

Grimes later wrote: “‘Roman numerals. Looks better tbh.”

She later added: “One dash is allowed”.

The couple have previously explained the meaning behind the name, breaking it down into its component elements.

Apparently, “X” represents the “unknown variable”.

“Æ” is the “elven spelling” of “Ai”, which means love in Chinese – and is also an acronym for artificial intelligence.

And the “A-12” is their “favourite aircraft”.

Speaking on the Joe Rogan podcast several days after the baby’s birth, SpaceX founder Musk explained how to pronounce the name: “It’s just X, the letter X. And then, the Æ is, like, pronounced ‘Ash’. And then, A-12.”

However, Grimes has previously told fans the Æ is pronounced like the two letters.

Æ is originally a Latin symbol, with some pronouncing it as “ash” and others as the letters A and E, which may explain the confusion.

Musk has said the unusual name was Grimes’ idea, but that the A-12 bit was his contribution. He’s yet to say whether he’s a fan of the Roman numerals.

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The 32-year-old singer and 48-year-old Tesla co-founder have been in a relationship for more than two years and made their public debut as a couple at the 2018 Met Gala.

South African-born Musk, who is one of the world’s richest men, also has five children with his first wife, the Canadian author Justine Wilson.

Away from his fatherhood duties, the Tesla co-founder recently ignored government rules, reopening his California plant despite orders to stay closed during the coronavirus lockdown.