Media reports last week said Mueller and Sheen's 4-year-old twin sons had been removed by the Los Angeles County Department of Children and Family services and placed with Sheen's other ex-wife, actress Denise Richards.
Various reports said Mueller was seeking help for drug addiction and/or psychiatric issues.
"Despite reports to the contrary, Brooke is currently at UCLA Medical Center where she has been since being admitted May 3," Mueller's representative told Us Weekly Monday.
"Brooke will be [at UCLA Medical Center] for several more days, and will likely transition directly into a residential treatment facility to get help for prescription drug abuse," the publicist said.
"Brooke misses her children, and wants to get healthy so she can resume her life and get back to being a mom."
The publicist did not say what exactly led to the hospitalization.