Actress Catherine Zeta-Jones, who announced in 2011 that she had been diagnosed with bipolar II disorder, has checked into a health care facility for treatment.

A rep for the actress tells ABC News, "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."

READ MORE: Catherine Zeta-Jones Hopes to Remove Stigma Around Bipolar Disorder

TMZ.com reports the actress, 43, entered a treatment center on Monday to begin a 30-day program.

Zeta-Jones was "outed" with the disease in April 2011 after her husband, Michael Douglas, told Oprah Winfrey. Later that month, she told the world herself, through a statement issued by her publicist, that she had sought treatment for the disease, a manic-depressive illness most known for the unusual shifts in mood and energy that those with it experience.

In an appearance on "Good Morning America" last December, Zeta-Jones described her apprehensions about going public with her diagnosis.

"You know what, I'm sick of talking about it because I never wanted to be the poster child for this," Zeta-Jones said. "I never wanted this to come out publicly."

In her first treatment, Zeta-Jones spent five days in the mental health facility and then went on medication, according to reports at the time.

At that time, the Welsh star said, "if my revelation of having bipolar II has encouraged one person to seek help, then it's worth it."

Zeta-Jones has been in the spotlight recently, appearing with her husband at the Film Society of Lincoln Center's 40th Annual Chaplin Award Gala honoring Barbra Streisand in New York this month and singing at the Oscars in February.

The Oscar-winner has also increased her presence on the big screen, appearing recently in films including "Rock of Ages," "Playing for Keeps," "Broken City" and "Side Effects."

"Everyone has things going on and we deal with them the best we can," Zeta-Jones said on "GMA" in December." "We can't jump from the rooftops shouting, you know, about, 'I have this, look at me, victim.' No. We all have issues in life and I'm really happy that I have great friends, great support and that's all I can do."