A well-known organizer for numerous celebrities went public Monday, claiming tidying sensation Marie Kondo stole her folding method and has been passing it off as her own.

Linda Koopersmith, known as “The Beverly Hills Organizer,” told Page Six that Kondo’s folding method — which has helped make her a television sensation and a best-selling author — is actually a technique Koopersmith created nearly 30 years ago.

“What Marie calls her KonMari Method, is actually a folding technique created by me 27 years ago,” Koopersmith told Page Six. “It was published in my book in 2005, it was shown on the TV show Clean House for years, and seen on YouTube videos.

“I invented that upright folding method when my daughter was 3 to organize her drawers so she could see everything,” Koopersmith added. “When I first saw Marie demonstrate my fold on TV as her own, it was so upsetting. I felt like somebody had stolen my baby.”

Koopersmith, whose celebrity clients include Serena Williams, Jennifer Lopez, and Derek Jeter, showcased her “upright folding technique” on the Style Network’s Clean House from 2003 to 2006. It was also featured in her 2005 book, The Beverly Hills Organizer’s Home Organizing Bible.

“Linda Koopersmith has been the queen of upright folding since we worked together on the Emmy winning Clean House. I’ve always said Linda is the only person I know who can fold your underwear to look like origami!” actress Niecy Nash, who hosted Clean House from 2003 to 2010, told Page Six. “I was also there when she discovered that she wasn’t given credit for her technique that others have claimed as their own.”

Koopersmith’s comments come on the same day Kondo made an appearance at the Cannes Lions festival, where she said her tidying methods — which includes discarding objects that no longer create joy — once helped fix a broken marriage. The Netflix star did not address Koopersmith’s comments.

While Kondo’s Netflix show Tidying Up with Marie Kondo won her millions of fans (and led to a surge in donations to Philadelphia thrift stores), she’s also had some high-profile critics. Former Project Runway star Tim Gunn said he wasn’t a believer of Kondo’s methods and turned down the opportunity to interview her twice.

“I have a huge number of books, as I’m sure you do. Do they all spark joy? Roget’s Thesaurus does not spark joy. Am I going to get rid of it? No!” Gunn said back in April on The One Way Ticket Show podcast. “I learned nothing that helped me with this whole process.”

Kondo was also criticized by members of the National Association of Professional Organizers, who complained anonymously to the New York Times back in 2016 that her once-in-a-lifetime organizing method was “too draconian” and that most clients couldn’t live in Kondo’s world. But Kondo recently told the Los Angeles Times that much of the criticism stems from misinformation about her method.

“There was some information — like you should limit yourself to 30 books — that was completely misconstrued, and was spread around as if it was part of my message,” Kondo said. “But I do feel that it’s a good thing for my method to be turned into a discussion. As long as it becomes an opportunity for everyone to start thinking about tidying and their way of life, I think that’s a positive.”

Netflix has not yet announced whether it will give Kondo’s show a second season.