Elon Musk and Grimes change their newborn baby's name

California, United States

Tesla and SpaceX CEO Elon Musk and his girlfriend singer and musician Grimes have changed their baby's name.

Earlier this month, Tesla and SpaceX CEO Musk announced the birth of the baby boy in a post on Twitter, revealing his son was called "X Æ A-12 Musk."

Also read: Name of Elon Musk's newborn baby not 'acceptable' in California

However, speculation arose that the unusual moniker might fall foul of the law in California, where the couple live, as names can only use the 26 alphabetical characters of the English language, according to the state constitution.

The slight variation in the name was revealed by Grimes on her Instagram page on Sunday when a user asked her if she had changed her baby’s name because of California laws and what the new name was.

"X Æ A-Xii" wrote the singer in response, without confirming the reason for the change.

The singer also responded to another comment, saying: "Roman numerals. Looks better tbh."

Musk, who already has five sons from his previous marriage to author Justine Wilson, said that it was girlfriend and Canadian singer Grimes who had come up with the name for their son.

She had explained the meaning of each character of her baby's name in a Tweet.