According to Pebe Sebert, her daughter was under enormous amounts of pressure to lose weight from people in her camp, including her producer Dr. Luke.
"Dr. Luke had been telling her how she had to get in shape and lose weight and all this stuff. She was exercising and dieting and ultimately doing everything she could, but not getting thin fast enough," Sebert told People magazine. "And that's when she first became bulimic."
"Dr. Luke told a friend of ours he thought she looked like a refrigerator on her latest video, and could she please try to control her weight," the 26-year-old's mom adds.
"After she went on a 14-day juice cleanse, he said, 'Thank God you finally got rid of the weight! We've all been talking about it!' So she felt like she couldn't trust anyone."
Sebert shared that just before the holidays, Ke$ha had a breakdown and confessed what was going on, telling the mag that the singer "called me from the gas station after she'd thrown up everything, and admitted how much she'd been doing it."
However, a rep for Dr. Luke tells People, "These statements and allegations concerning Dr. Luke are completely false. It is unfortunate that at a time Ke$ha is suffering immensely and trying to heal at a treatment center, her mother is taking this approach with the media. I give Ke$ha my utmost support and well wishes for a quick return to health."
Ke$ha entered rehab for her disorder last week. "I'm a crusader for being yourself and loving yourself but I've found it hard to practice," she tells E! News. "I'll be unavailable for the next 30 days, seeking treatment for my eating disorder...to learn to love myself again. Exactly as I am."