Published Friday, 01 June 2012
The troubled reality TV star, who has two sons with the actor, has long suffered substance abuse problems and she checked into a drug recovery centre late last year in a bid to regain her health.
She subsequently enrolled in an outpatient program, but she is now back in a rehab centre for further treatment.
Mueller's representative Steve Honig tells Celebuzz.com: "As part of her ongoing treatment and as planned, she voluntarily checked herself into a rehab facility several weeks ago."