SEE | Elon Musk shares rare photo of adorable son X Æ A-12 to mark his milestone birthday

Elon Musk and Grimes's eldest son, X Æ A-12, nicknamed X, celebrated his fourth birthday on 4 May. To mark his son's crown birthday, Musk posted a photo of him on X (formerly known as Twitter).

"Lil X turns 4 today on May 4th," Musk said on the app, along with the image which shows X smiling while wearing a Cybertruck t-shirt and sitting on what looks like a table.

Musk rarely posts photos of any of his children.

At the 2018 Met Gala, Grimes and Musk first debuted their relationship. The two ended their relationship in March 2022.

Last year, Grimes filed a suit against Musk over parental rights of their three children, Techno Mechanicus, X Æ A-12 and Exa Dark Sideræl.

In a deleted X reply post, Grimes wrote:

"Tell Shivon [Zilis] to unblock me and tell Elon to let me see my son, or please respond to my lawyer. I have never been allowed to see a photo of these children until this moment, despite the situation utterly ripping my family apart."

Grimes only has three children - the ones she shares with Musk.

Musk is the father of 11 children; the others are Nevada Alexander, Griffin, Vivian, Kai, Saxon and Damian Musk. Elon Musk also had twins with the Neuralink director of operations and special projects, Shivon Zilis, in 2021.

Musk is currently the third richest man in the world, with a reported net worth of $198.4 billion, according to Forbes. Jeff Bezos is the second richest, while Bernard Arnault and family tops the list with $213.6 billion.