A legendary actress is getting treatment.

Catherine Zeta-Jones has checked in to a treatment center for bipolar disorder, according to TMZ.

The 43-year-old star of The Legend of Zorro entered the facility on April 29 and is apparently going to take part in a 30-day program.

Sources say that there wasn't any particular incident that triggered her need to seek treatment, but this is just her way of staying on top of things.

"It's maintenance," says one source. 

Catherine's last public appearance was on April 22 with husband Michael Douglas on the red carpet at the 40th Anniversary Chaplin Award Gala at NYC's Lincoln Center.

She has publicly addressed her struggles with bipolar disorder over the years, and she previously sought treatment for it in April 2011.

Catherine has been busy with her career of late and stars in this summer's Red 2. She recently appeared in Playing for Keeps and Rock of Ages, and she won an Oscar for 2002's Chicago. 

She married actor Michael Douglas in 2000, and they have two children. He recently battled throat cancer.

We're wishing her all the best.

Source: TMZ