Brooke Mueller -- Checks In to Full-Time Rehab

Brooke Mueller has had a change of heart ... and has checked herself in to a full-time rehab center ... TMZ has learned.

Mueller's rep, Steve Honig, tells TMZ, "After further reflection and consideration, Brooke has decided to remove herself from the media spotlight and has entered a long-term in-patient treatment center where she can focus on her recovery without distraction."

"She has already arrived at the facility and, out of respect for her privacy, no further information will be released about her treatment. Brooke’s goal is to maintain her sobriety and she believes this is the best option to reach that goal."

“Brooke will retain custody of the children, who will remain in their home and familiar surroundings and be under the care of their longtime nanny. Charlie and Brooke’s parents fully support her decision and everyone recognizes the importance of maintaining the children's normal routine."

Brooke had previously decided she would enter an outpatient rehab program to be with her kids -- so much for that.

Brooke was seen boarding a private jet in Los Angeles last night ... presumably headed for her rehab center. Mueller was seen smiling and chatting with her entourage before getting on board.

No word on where the rehab center is located.