Catherine Zeta-Jones, who has been by husband Michael Douglas's side during his cancer fight, has sought mental health treatment for herself, her rep says. "After dealing with the stress of the past year, Catherine made the decision to check in to a mental health facility for a brief stay to treat her Bipolar II disorder," the rep says in a statement. "She's feeling great and looking forward to starting work this week on her two upcoming films."

Zeta-Jones, 41, spent about five days in the unidentified facility, a friend tells PEOPLE.

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