Catherine Zeta-Jones Back in Treatment for Bipolar II Disorder
"There was no big problem," sources say.
"Catherine has proactively checked into a health care facility. Previously Catherine has said that she is committed to periodic care in order to manage her health in an optimum manner," her rep said.
Sources for PEOPLE added this is simply a way for doctors to monitor Zeta-Jones' medication.
"There was no big problem. This was just a good time to do it. She is in between projects. This has always been part of the plan. She would manage her health. She is vigilant about it."
Zeta-Jones, 43, who is married to actor Michael Douglas, was previously treated for bipolar II disorder in 2011.
She'll next appear in the movie Reds 2, out July 19.