Grimes is suing her ex Elon Musk over a matter involving their three children.

Born Claire Boucher, the “Genesis” performer filed a “petition to establish parental relationship” on September 29 in a California court, court records obtained by Page Six show.

The request intends to have the court identify the legal parents of a child when they are unmarried.

Although the docket for the case is public, the filings have been sealed; however, it does not appear that the Tesla co-founder has responded to Grimes’ petition.

She also has yet to request child support or custody rights.

Grimes, 35, and Musk, 52, began dating in 2018 and had an on-again, off-again relationship until September 2021 when they split for good.

The Canadian artist gave birth to their firstborn, a son named X Æ A-Xii, in May 2020, and the former couple went on to quietly welcome daughter Exa Dark Sideræl, aka Y, via surrogate in December 2021.

In September, journalist Walter Isaacson’s “Elon Musk” biography revealed the SpaceX founder and Grimes secretly had a third child, a boy named Techno Mechanicus, whom they have affectionally dubbed Tau.

It’s unclear when Tau was born.

Grimes’ petition comes just weeks after she pleaded on Twitter with Musk to allow her to see their son.

In response to Isaacson’s tweet sharing photos of the billionaire’s twins, Strider and Azure, whom he shares with Shivon Zilis, the “Oblivion” singer wrote in a since-deleted tweet, “Tell Shivon to unblock me and tell Elon to let me see my son or plz respond to my lawyer.

“I have never even been allowed to see a photo of these children until this moment, despite the situation utterly ripping my family apart.”

Days later, Grimes explained on the same platform that she had connected with Zilis, 37, to “de-escalate” the feud.

“I spoke with Shivon at length finally, which was long overdue. This wasn’t her fault, plz don’t be angry at her!” she began her missive.

“We respect each other a lot and we’re excited to become friends and have the kids grow up together.”

Zilis responded to the musician, saying it “all ended up for the best.”

Musk, who is a father of 11 and has been divorced three times, and Zilis secretly welcomed their twins in November 2021 following his split from Grimes, though news of the newborns did not surface until eight months later.