X Æ A-12: Elon Musk, Grimes change baby's name following California law

MANILA, Philippines — Tesla head Elon Musk and girlfriend, singer Grimes, recently changed the unusual name of their new baby because of a Californian law.

The couple revealed earlier this month that their baby will be named X Æ A-12, but a California law stipulates that only alphabetic letters can be used in a newborn's name.

On Instagram, a fan asked Grimes if the baby has a new name because of the law.

"Did you change the baby name because of Californian laws ? What is the baby's new name?" the fan wrote on Grimes' Instagram photo.

“X Æ A-Xii,” Grimes replied, changing the numbers to Roman numerals. She added in the comments, “looks better tbh.”

The California Department of Public Health Vital Records Handbook explains the requirements for completing a birth certificate: "The form is to be completed using the 26 alphabetical characters of the English language." Some punctuation symbols are allowed when necessary, like in a hyphenated last name or one with an apostrophe.

Using numbers, however, is not allowed under those rules, and using pictures, like an emoji or ideogram, in a name is also forbidden.

RELATED: Welcome baby X Æ A-12: Musk, Grimes may face problems registering name