Elon Musk and Grimes reveal Y, their  second baby

Elon Musk and Grimes reveal Y, their  second baby

Singer Grimes welcomed another baby with Elon Musk, the richest man in the world.

They welcomed their daughter Exa Dark Sideræl via surrogate in December.

Grimes broke the news, thanks to the baby crying upstairs, as she welcomed a reporter into her home for an interview.

Their daughter's name Exa refers to a computing term, exaFLOPS, while Dark represents "the unknown". They've also  nicknamed her Y.

Grimes wanted to name her daughter Odysseus Musk, but Tesla's CEO settled on Exa Dark Sideræl instead.

Musk and Grimes also parent a 22-month-old son X Æ A-12.

Grimes is a Canadian artist who has a net worth of $10 million, she began dating Musk in 2018.

Musk, the richest man on earth, has a net worth of $302 billion.

Musk is saving up to do more for humanity and is working to build a city on Mars.

Musk won't be leaving his wealth to his kids. He has pledged to use it to help solve society's problems.