Charlie Sheen's ex-wife Brooke Mueller has checked back into rehab as part of her "ongoing treatment" for addiction issues.

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 center 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."