The Good Wife star was set to appear at a New York cocktail party in support of her newly-released children's book, Three Magic Balloons, on Thursday (05May16), but she pulled out of the event.

It is unclear how long the 49-year-old has been battling the disease, but she attended the CARE National Conference in Washington, D.C. earlier this week (ends06May16).

"I sat with the extraordinary #MadelineAlbright," she wrote on "What an accomplished and amazing woman. Congratulations to CARE for their 70th anniversary."

She also recently celebrated the series finale of her long-running TV hit The Good Wife, which comes to an end on Sunday (08May16).

"Thursday night was our series finale party at MOMA in New York," she wrote to fans on social media. "It was an amazing evening. Thanks to each and every one of you for your amazing support and love..."