New York (CNN Business) Rush Limbaugh, the most prominent political radio host in the United States, said Monday that he is beginning treatment for lung cancer.

Limbaugh, 69, told his radio audience Monday that he was diagnosed with an advanced stage of the disease. He said the diagnosis was confirmed on January 20.

"I wish I didn't have to tell you this, and I thought about not trying to tell anybody, I thought about trying to do this without anybody knowing, because I don't like making things about me," Limbaugh said. But "there are going to be days that I'm not going to be able to be here, because I will be undergoing treatment, or I'm reacting to treatment."

Limbaugh has been hosting "The Rush Limbaugh Show" in national syndication for 31 years. He is a Republican party icon and a close ally of President Trump's.

The president recently called Limbaugh "a major star who never wavered despite the Fake News Hits he has had to endure. His voice is far bigger than theirs!"

Read More