Actress Jenna Fischer, known for her role as Pam Beesly in the sitcom “The Office,” revealed that she was diagnosed with breast cancer last year but is now cancer-free after receiving treatment.

Fischer said in a post on Instagram on Tuesday she was diagnosed with Stage 1 triple-positive breast cancer in December of last year after an inconclusive mammogram led to a breast ultrasound. 

“I never thought I’d be making an announcement like this but here we are. Last December, I was diagnosed with Stage 1 Triple Positive Breast Cancer. After completing surgery, chemotherapy and radiation I am now cancer-free,” Fischer wrote. 

The Instagram post included a series of slides detailing her cancer diagnosis and treatment. She also urged her followers to schedule their annual mammograms. 

Fischer wrote that triple-positive breast cancer is an aggressive form of cancer but is highly responsive to treatment. She said she underwent a lumpectomy to remove a tumor in January, followed by 12 rounds of weekly chemotherapy and weeks of radiation. “Luckily my cancer was caught early and it hadn’t spread to my lymph nodes or throughout the rest of my body,” she wrote. 

“I’m happy to say I’m feeling great,” Fischer added.

Fischer also revealed she had lost her hair during the chemotherapy and had been wearing wigs.

“I’m making this announcement for a few reasons. One, I’m ready to ditch the wigs. Two, to implore you to get your annual mammograms,” she wrote.

“I’m serious, call your doctor right now,” she added. “My tumor was so small it could not be felt on a physical exam. If I had waited six months longer, things could have been much worse. It could have spread.”

In the post she also thanked her medical team, husband, family and friends. “It takes a village to fight cancer, and I have had an amazing village,” Fischer, a mother of two children, 10 and 13, wrote. 

She also thanked her best friend and “The Office” co-star Angela Kinsey, “who protected and advocated for me.”

Fischer and Kinsey host a podcast, “Office Ladies,” where they discuss episodes of “The Office” and share behind-the-scenes stories about the sitcom.

“For a long time, she was the only person in my workspace who knew,” Fischer wrote. “When I lost my hair, she wore hats to our work meetings so I wouldn’t be the only one. When I needed a break, we took one. I am so lucky to have a career with this kind of flexibility. Cancer treatment requires a lot of flexibility. For a gal who likes to plan, that was a hard adjustment. But, continuing to work has brought so much joy to my life during treatment.”