Elon Musk allegedly welcomed his thirteenth child five months ago, author Ashley St. Clair claims.

St. Clair posted a lengthy message on X Friday, saying that she and the Tesla founder have a child together.

“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.

“I intend to allow our child to grow in a normal and safe environment,” St. Clair, who has been an outspoken supporter of conservative ideologies, added.

“For that reason, I ask that the media honor our child’s privacy, and refrain from invasive reporting.”

The 31-year-old also captioned her post with the Latin phrase, “Alea Iacta Est,” which translates to: “The die is cast.”

In a follow-up tweet, she wrote, “In all sincerity, appreciate the kind words. Wish I did not feel the need to make a statement. Kids should be off limits for journalists. Will be spending time with my family & logging off for a while.”

A rep for the X owner, 53, didn’t immediately respond to Page Six’s request for comment.

St. Clair is best known for her children’s book, titled “Elephants Are Not Birds,” which follows “Kevin as he learns that even though he can sing, he is not a bird, even if Culture insists that he is.”

Musk, who first became a dad in 2002, is already a father to 12 children.

Musk welcomed six kids — late son Nevada, twins Griffin and Vivian, 20, and triplet sons Kai, Saxon and Damian, 19 — with his first wife, Justine Wilson. They tied the knot in January 2000 but split after eight years of marriage.

Musk welcomed son X AE A-XII — aka X — with singer Grimes in 2020, two years after they started dating.

After their split in September 2021, Musk and Grimes welcomed daughter Exa Dark Sideræl Musk, who was given the nickname Y, via surrogate three months later.

They quietly had a third child, Techno Mechanicus — aka “Tau” — around June 2022.

Musk also shares 2-year-old twins, Strider and Azure, and a 1-year-old child, whose name and sex has not been revealed, with Shivon Zilis.