Catherine Zeta-Jones has checked into a clinic for the second time for treatment of bipolar disorder, her reps confirmed to Page Six last night. The 43-year-old actress and wife of “Wall Street” star Michael Douglas yesterday went to an unnamed treatment center where she is expected to stay for 30 days. Her spokeswoman said last night, “Catherine has pro-actively checked into a health-care facility,” adding, “Previously, Catherine has said that she is committed to periodic care in order to manage her health in an optimum manner.” Zeta-Jones had sought help in 2011, when she reportedly went to a detox center at a hospital in New Canaan, Conn. At the time, her publicist said Zeta-Jones had received mental-health treatment to help her cope with personal trauma, which included Douglas’ battle with cancer: “After dealing with the stress of the past year, Catherine made the decision to check into a mental-health facility for a brief stay to treat her bipolar II disorder.” Zeta-Jones was last seen in public on April 22, when she hit the red carpet at the 40th Anniversary Chaplin Award Gala at Lincoln Center with her husband by her side. Family sources tell us, “Michael is extremely supportive of Catherine.” She told InStyle magazine about her diagnosis, “It’s been an intense time, in good ways and bad. You find out who you really are and who you are married to. You find things inside yourself you never imagined were there.”