Gregg DeGuire/Getty; Amy Sussman/Getty
The source says that the Bullet Train actor, 58, and the model, 31, "are spending a lot of time together." However, they add that "friends aren't sure if it's serious," and the two don't "appear to be 'dating' formally."
A rep for Ratajkowski did not immediately respond to PEOPLE's request for comment.
The outlet reported the filing was contested, meaning the terms of the divorce have not been resolved between the spouses.
Emma McIntyre /VF20/WireImage Emily Ratajkowski with her husband Sebastian Bear-McClard
In July, a source close to Ratajkowski confirmed to PEOPLE that the couple had broken up.
"They split recently. It was Em's decision. She is doing okay. She is strong and focused on her son. She loves being a mom," the insider told PEOPLE at the time.
As Page Six first reported, speculation about a possible separation began in July after the model was seen running errands without her wedding ring. She also was not wearing it in her Instagram photos this summer.
The duo was first romantically linked in 2018 after they were spotted showing PDA on Valentine's Day. After dating for only a few weeks, Ratajkowski and Bear-McClard tied the knot in a surprise ceremony at N.Y.C.'s City Hall that same month.
RELATED VIDEO: Emily Ratajkowski and Sebastian Bear-McClard Split After 4 Years of Marriage: Source
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"Brad has dinner with his younger kids when they are all in L.A. Since the kids are older now, they have their own life and friends. Brad still has a pretty good relationship with them," the source said in July.
Jolie and Pitt, who were declared legally single by a judge back in 2019, are parents to Maddox, 21, Pax, 18, Zahara, 17, Shiloh, 16, and 14-year-old twins Vivienne and Knox.
"Brad has his movies, he has Miraval and he has these other [passions]," said the source. "He loves architecture, he loves creativity. He's living his best life under the circumstances."