Zilis and Musk also share twins, Strider and Azure, 3, and daughter Arcadia, 1

Elon Musk and Shivon Zilis. Photo: Kevin Mazur/MG22/Getty; Shivon Zilis/shivonzilis.com

Elon Musk and Shivon Zilis have welcomed their fourth child together.

Zilis made the announcement in an X post published Friday, Feb. 28, revealing she and Musk, 53, are parents to a second son: Seldon Lycurgus. She did not reveal when Seldon was born.

“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 ♥️.”

Musk simply replied to Zilis’ X post, “♥️.”

A source exclusively tells PEOPLE, Musk “really loves Shivon.”

The Tesla founder and Zilis revealed in November 2021, that they secretly welcomed twins, son Strider and daughter Azure. The twins were born just weeks before he and musician Grimes welcomed a baby girl, Exa Dark Sideræl, via a surrogate, according to court documents published by Insider in July 2021.

Less than three years later, on Feb. 28, 2024, the pair welcomed their third child together, Arcadia. On Friday, Feb. 28, 2025, she celebrated her daughter’s first birthday with an X post. “Happy 1st birthday, darling Arcadia. Mommy loves you with all her heart 💞,” she wrote.

Elon Musk and Shivon Zilis with their twins Strider and Azure ; Elon Musk with son X.Shivon Zilis/ X ; Elon Musk/ X

Nearly two years after Musk and Zilis welcomed their twins, Grimes posted to X in September 2023 after tweeting and deleting about the blended family dynamics, saying she and Zilis had connected. She said they were now on the same page about the conditions under which they both separately welcomed children with Musk, weeks apart.

Zilis responded on X, “At the end of the day it all ended up for the best! Thank you for taking the time to really connect and understand each other. So glad we had such a wonderful talk, was insanely overdue. You’re a total badass and I respect you very much as well. I can’t wait for kiddo play date and congrats on baby Tau as well!”

Grimes and Musk have three children, including son X Æ A-12, 4, daughter Exa Dark Sideræl, 3, and son Techno Mechanicus aka Tau, 2.

Shivon Zilis, mother of four of Elon Musk’s 14 kids.Shivon Zilis X

The news of Musk’s 14th child follows author Ashley St. Clair’s Friday, Feb. 14 X announcement that she and Musk welcomed his thirteenth child five months ago, a son named R.S.C.

“Five months ago, I welcomed a new baby into the world. Elon Musk is the father. I have not previously disclosed this to protect our child’s privacy and safety, but in recent days it has become clear that tabloid media intends to do so, regardless of the harm it will cause,” she wrote.

St. Clair’s representative Brian Glicklich, posted a statement on X on Saturday, Feb. 15, writing, “Ashley & Elon have been privately working towards the creation of an agreement about raising their child for some time.”

“We are waiting for Elon to publicly acknowledge his parental role with Ashley, to end unwarranted speculation,” he continued.

On Friday, Feb. 28, a judge ordered Musk to appear at a May 29 hearing over R.S.C.’s custody. Musk first became a father in 2002 when his ex-wife, Justine Wilson, welcomed their son Nevada Alexander, who tragically died at 10 weeks old. The two went on to have five more children: twins Vivian and Griffin, 20, and triplets Kai, Saxon and Damian, 19.