Pictures of 'Little Couple' Star Jen Arnold and Husband Bill Klein

36th Annual Gracie Awards Gala - InsideJennifer Arnold (L) and Bill Klein speak during the 36th Annual Gracie Awards Gala at the Beverly Hilton Hotel on May 24, 2011 in Beverly Hills, California. (Getty Images)more pics »The stars of TLC's The Little Couple shared some hard news today: Jen Arnold has been diagnosed with a rare form of cancer. The 39-year-old said that she's "currently undergoing treatment, including surgery and chemotherapy."

Jen Arnold (Bauer Griffin)
The reality star added that the outlook is bright: "I am very fortunate as the prognosis is good. While there is never a good time to get news like this, getting it just as we are building our new family is tough in many ways ... But being surrounded by the love of my husband and our two beautiful children is actually in many ways giving me the strength to fight it even stronger."

Arnold and husband Bill Klein recently welcomed a two-year-old from India into their family. They're already parents to Will, 3, who was adopted from China.

Arnold and Klein have not released any further information about the type of cancer she is battling.

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