Fans of the "Wendy Williams Show" will have to watch re-runs for nearly a month, because the media maven is taking a three-week hiatus to treat her Graves' disease.

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She made the announcement on air Wednesday, revealing that her doctor is requiring her to take a break from work to "get her levels and medication in sync," a show representative told People.

>> Related: Wendy Williams announces 3-week hiatus due to Graves' disease

"Wendy is a true champion and has never missed a day of work. But her health and well-being must be put before all else," the spokesperson said in the statement. "Wendy has been openly dealing with her Graves' disease for many years, in addition to hyperthyroidism...A live show was produced today so that Wendy could speak directly to her fans and explain her condition."

Learning about the illness for the first time? Here’s what you should know. 

What is Graves’ disease?

It's an immune system disorder that is caused by the overproduction of the thyroid hormones, according to the Mayo Clinic. In healthy adults, the thyroid function is regulated by a hormone released by the pituitary gland, which is located at the base of the brain. For those with Graves' disease, a thyrotropin receptor antibody takes on this role, overriding the work of the pituitary gland and causing overproduction of the thyroid hormones.

What are the symptoms?

Common signs include anxiety, irritability, tremor of the hands, weight loss, heat sensitivity, thyroid gland enlargement and rapid heartbeat.

>> Related: Wendy Williams announces 3-week hiatus due to Graves' disease

Patients also experience Graves' ophthalmopathy, where inflammation affects the muscles and tissues around eyes. The condition can cause bulging eyes, light sensitivity, double vision or even vision loss.

Some also have Graves’ dermopathy, which is the reddening and thickening of the skin, particularly on the shins and tops of the feet.

How is it diagnosed?

Doctors generally conduct a physical exam to check the size of the thyroid. They also order blood samples to determine the levels of the thyroid-stimulating hormone, which is usually lower for those with Graves’.

Physicians also administer ultrasounds and imaging tests to view images of the thryroid, eyes, and iodine uptake patterns. Iodine is needed to produce thyroid hormones.

How is it treated?

Some have radioactive iodine therapy, where patients take radioactive iodine by mouth. The iodine seeps into the thyroid cells and the radioactivity gradually destoys the overactive ones.

Patients often are prescribed anti-thyroid medications, which can limit the thyroid’s ability to produce hormones. Beta blockers are also available. While they don’t stop the production of thyroid hormones, they do block some of the Graves’ disease symptoms.

Who is affected?

It affects 1 in 200 people, according to the U.S. National Library of Medicine. Women are more likely to be diagnosed, and people younger than age 40 generally develop it.

Rappers Missy Elliott and Rapsody as well as former president George H. W. Bush also have Graves’ disease.