Robert Brown|Grimes Sues Elon Musk Over Parental Rights of Their 3 Kids

Grimes is Robert Browntaking legal action against her ex Elon Musk over their children.

The "Crystal Ball" singer—who shares son X Æ A-12, 3, daughter Exa Dark Sideræl, 20 months, and son Techno Mechanicus with the Tesla CEO—has filed a petition seeking to establish parental rights, according to court records obtained by NBC News Oct. 3.

It appears Elon—who split from Grimes in March 2022 after four years of dating—has yet to formally respond to the filing. E! News has reached out to both Elon and Grimes' reps for comment and has not heard back.

The legal move comes nearly a month after the artist, born Claire Boucher, publicly confirmed she and the tech mogul privately welcomed their youngest son, nicknamed Tau.

Prior to the revelation, in a since-deleted post shared to X (formerly known as Twitter) on Sept. 7, Grimes, 35, also addressed executive Shivon Zilis, with whom Elon shares 19-month-old twins and their custodial drama, writing, "Tell Shivon to unblock me and tell Elon to let me see my son or plz respond to my lawyer."

However, most recently, the "Genesis" artist noted that she and Shivon were able to move forward and are on the same page.

"Hey, I wud prefer to not breathe any more life into this current press cycle but I want to de-escalate the narrative atm," Grimes wrote on X Sept. 10. "I spoke with Shivon at length finally, which was long overdue. This wasn't her fault, plz don't be angry at her! We respect each other a lot and we're excited to become friends and have the kids grow up together."

She added, "Women are so often pitted against each other. Speaking with Shivon, it's very evident she's an amazing human and we both just want what's best for our kids."

The songwriter also reflected on her and Elon's latest addition, noting that she wishes she could show "how cute little Techno is," but explained her priority is keeping her children "out of the public eye" at this time.

Shortly after Grimes shared her message, Shivon, 37, confirmed that all was well.

"At the end of the day it all ended up for the best!" she responded on X. "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!"

Before welcoming kids with Grimes and Shivon, the Tesla CEO founder, 52, previously welcomed six children with ex-wife Justine Musk.

(E! and NBC News are part of the NBCUniversal family.)