Catherine Zeta-Jones has readmitted herself to hospital for "maintenance" treatment for bipolar II disorder.
The actress, 43, checked into a clinic on Monday according to gossip website TMZ and is expected to complete a 30-day programme of treatment.
Sources quoted by the website said the treatment is “maintenance” for the disorder, about which the Academy Award winner has spoken publicly in the past.
The Welsh-born actress said in an interview last November that she would like to combat the “stigma” surrounding mental illness, having been diagnosed with manic depression, bipolar disorder II, just over two years ago.
She spent five days in a rehabilitation clinic 2011 when her condition worsened as a result of months of worry while her husband Michael Douglas battled Stage Four throat cancer.
“I'm not the kind of person who likes to shout out my personal issues from the rooftops but with my bipolar becoming public, I hope fellow sufferers will know it is completely controllable,” Zeta-Jones told US InStyle magazine last year.
“I hope I can help remove any stigma attached to it, and that those who don't have it under control will seek help with all that is available to treat it.”
She said the experience had helped her to gain appreciation for life and had strengthened her 12-year marriage to Douglas.
“You find out who you really are and who you are married to. You find things inside yourself you never imagined were there,” she said.
Zeta-Jones began her career as a stage actress, gained fame on ITV’s The Darling Buds of May before moving to Hollywood where she was cast in The Mask of Zorro, Traffic and Entrapment.
She married Douglas, who is 25 years her senior, in 1998 and the couple have two children.
Zeta-Jones was last seen in public two weeks ago when she attended the 40 Anniversary Chaplin Award Gala at Lincoln Center accompanied by Douglas.
Bipolar disorder is an imbalance in the brain's mood regulating system which can cause episodes of hypomania and depression. It can be triggered by factors such as grief and stress and is thought to affect at least 1 percent of the adult population in the UK.