“Discussed with Elon and, in light of beautiful Arcadia’s birthday, we felt it was better to also just share directly about our wonderful and incredible son Seldon Lycurgus. Built like a juggernaut, with a solid heart of gold. Love him so much," Zilis wrote, also revealing the name of the couple's previously-born child in the announcement.

Billionaire Elon Musk, who is a close adviser to U.S. President Donald Trump, has another child, his 14th. His latest child, a son, is with Shivon Zilis, an executive at Musk's Neuralink with whom he already has three other children.

Shivon Zilis, the Neuralink executive who already has three children with Elon Musk, took to the billionaire’s preferred social media platform on Friday to announce that the pair had welcomed a fourth child into the world: Seldon Lycurgus.