Originally appeared on E! Online
Elon Musk's family tree is growing once again.
The Tesla CEO confirmed he has welcomed another baby, his fourth with tech exec Shivon Zilis.
The pair — who also share twins Strider and Azure, 3, as well as 12-month-old Arcadia — announced the arrival of son Seldon Lycurgus on social media Feb. 28.
"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," Zilis wrote on X. "Built like a juggernaut, with a solid heart of gold. Love him so much."
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 ♥️
— Shivon Zilis (@shivon) February 28, 2025
Musk — who allegedly welcomed his 13th child with author Ashley St. Clair five months ago — responded with a heart emoji.
Earlier in the day, Zilis celebrated Arcadia's first birthday with a tribute, writing, "Happy 1st birthday, darling Arcadia. Mommy loves you with all her heart."
PHOTOS 2025 Celebrity Babies
The pair first conceived son Strider and daughter Azure via IVF in 2021, before confirming in June 2024 that they had welcomed their third child.
"All our friends and family know," the SpaceX founder told Page Six at the time. "Failure to issue a press release, which would be bizarre, does not mean 'secret.'"
Zilis — an artificial intelligence specialist who has worked at Musk's Neuralink — explained why she wanted to have children with the 53-year-old.
"He really wants smart people to have kids, so he encouraged me to," Zilis is quoted as saying in Walter Isaacson's 2023 biography "Elon Musk." "If the choice is between an anonymous sperm donor or doing it with the person you admire most in the world, for me that was a pretty f--king easy decision."
In an appearance with French President Macron at the White House, President Trump commented on Elon Musk’s demand over the weekend that federal employees detail their work accomplishments in an email.
She added, "I can't possibly think of genes I would prefer for my children."
He also shares twins Vivian and Griffin, 20; triplets Kai, Saxon and Damian, 19; and a baby Nevada who died in 2002 at 10 weeks old with ex Justine Wilson, as well as kids X Æ A-12, 4, Exa Dark Sideræl, 3, and Techno Mechanicus, 2, with Grimes.
More recently, St. Clair took legal action against Musk by submitting a paternity petition to legally declare him the father of her child, as well as filing for sole custody.
"Five months ago, I welcomed a new baby into the world. Elon Musk is the father," St. Clair wrote on X Feb. 14. "I have not previously disclosed this to protect our child's privacy and safety, but in recent days it has become clear that the tabloid media intends to do so, regardless of the harm it will cause."
The influencer noted, "I intend to allow our child to grow in a normal and safe environment. For that reason, I ask that the media honor our child's privacy, and refrain from invasive reporting."
E! News reached out to Musk's rep for comment and has not heard back. He hasn't publicly commented on St. Clair's child.
