After returning to his Premiere Networks-syndicated talk show on Friday, Rush Limbaugh was unexpectedly not on the air Monday, Feb. 10.

The host penned a memo that was posted on his website saying that he was hospitalized over the weekend with the flu. This, he says, is unrelated to his recent disclosure that he has been diagnosed with advanced lung cancer.

“Folks, really sorry I cannot be with you today,” Limbaugh wrote. “What I thought was the onset of just a cold during Friday’s show turned out to be the flu and I was in a super-secret hospital all weekend being successfully treated by the absolute best doctors.”

The controversial conservative radio host said he wanted to do his program but “my doctors are insisting on a veritable quarantine as I prep for the beginning of my treatment regimen” for his lung cancer.

Limbaugh says he plans to be back on Tuesday, Feb. 11. Ken Matthews hosted Monday’s show.

Upon his return Friday, after announcing the diagnosis a week before and receiving the Medal of Freedom from President Trump during the State of the Union, Limbaugh spoke of his “incredible week.” The outpouring of support “make(s) me one of the luckiest people alive,” he said.