Grimes is suing Elon Musk over their three children.
The singer, born Claire Boucher, filed a "petition to establish parental relationship" on Sept. 29 in a California court, according to court records obtained by Page Six.
The petition aims to have the court establish the legal guardianship of a child when the parents are not married.
While the case docket is accessible to the public, the documents submitted have been kept confidential.
However, it appears that Musk has not responded to Grimes' petition. Page Six further noted that Grimes has yet to request child support or custody rights.
Grimes, 35, and Musk, 52, began dating in 2018 and had an on-off relationship until their final separation in September, 2021.
Their first child together, a son named X Æ A-Xii, was born in May, 2020. Subsequently, the former couple quietly welcomed their daughter, Exa Dark Sideræl, known as Y, through surrogacy in December, 2021.
Then, in a surprise revelation from journalist Walter Isaacson's biography "Elon Musk" in September, it emerged that Musk and Grimes had a third child, a son named Techno Mechanicus, also referred to by the couple as Tau.
Last month, Grimes pleaded with Musk on social media to let her see their son
Taking to X, the singer accused Musk of "ripping my family apart" while claiming that the mother of his twins, Shivon Zilis, had blocked her on Twitter.
Grimes made her remarks while commenting on a post that featured a new image of Musk and the twins he had with Zilis.
"Tell Shivon to unblock me and tell Elon to let me see my son or plz respond to my lawyer," Grimes wrote, according to screenshots made available by the Daily Mail.
"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 clarified on X that she had reached out to Zilis, 37, to "de-escalate"
"I spoke with Shivon at length finally, which was long overdue. This wasn't her fault, plz don't be angry at her!" she wrote, according to Page Six.
"We respect each other a lot and we're excited to become friends and have the kids grow up together."
Zilis responded, saying it "all ended up for the best."