Right-wing radio host Rush Limbaugh said Monday that he’s been diagnosed with advanced lung cancer. “The upshot is that I have been diagnosed with advanced lung cancer. Diagnosis confirmed by two medical institutions back on January 20th,” Limbaugh told his listeners. “I thought about trying to do this without anybody knowing because I don’t like making things about me. But there are going to be days where I’m not going to be able to be here, because I’m undergoing treatment or I’m reacting to treatment... it is what it is.” Limbaugh, host of the The Rush Limbaugh Show, is one of the most popular talk-radio hosts in the U.S.—with about 15.5 million people tuning into his show.

While he didn’t endorse President Trump outright during the 2016 election, Limbaugh has come to the president’s defense more recently. He slammed Fox News for criticizing Trump, saying it should be re-named the “Fox Never Trumper Network,” and has recently praised the president, insisting he helped unite the Republican Party. “I think it is gonna be more and more obvious the Republican Party is Trump’s party,” he said.