Grimes has filed a petition against Elon Musk to establish parental rights.

The Canadian musician, 35, filed a "petition to establish parental relationship" in The Superior Court of California in San Francisco on Friday against Musk, 52, online records viewed by USA TODAY show. Court documents related to the case have been sealed.

Grimes and Musk share three children: sons X Æ A-Xii and Tau Techno Mechanicus and daughter Exa Dark Sideræl, also called "Y."

The petition begins the process of legally declaring the tech CEO as the father to their children for parents who are unmarried. It is sometimes used as the first step in establishing child custody or requesting child support, according to California Superior courts.

Grimes also filed a notice in court that same day to be open to "alternative dispute resolution methods," which typically include mediation, arbitration, negotiation, private judgment and more.

USA TODAY has reached out to reps for Grimes and her attorney for comment.

Grimes previously alleged Elon Musk was preventing her from seeing her child

The singer's petition Friday comes a month after Grimes alleged in a now-deleted tweet that Musk wasn't allowing her to see one of her children.

"Tell Shivon to unblock me and tell Elon to let me see my son or plz respond to my lawyer," Grimes wrote in response to Musk's biographer Walter Isaacson sharing a photo of the Musk, Shivon Zilis and the X CEO's twins he shares with Zilis.

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

The Canadian singer later shared on X, formerly Twitter, that she had a "long overdue" conversation with Neuralink executive Zilis. "We respect each other a lot and we're excited to become friends and have the kids grow up together," she said. "Communication about the twins wasn't handled super well in the past, but I now totally understand what happened and totally forgive the situation."

Grimes went on to praise Zilis, writing, "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."

Elon Musk has third child with Grimes,reveals baby's unique name

Elon Musk kids: X CEO's 9 children

Musk, who owns X and is also CEO to Space X, has five other children outside of his three with Grimes.

The tech mogul had triplets with his former wife, Justine Wilson, a Canadian author, whom he divorced in 2008. He also had twins with Zilis, born shortly before Grimes' youngest child.

Musk and Wilson lost a child, Nevada Musk, in 2002. The baby died from sudden infant death syndrome at 10 weeks old.

Contributing: Natalie Alund