"He was on the Today show this morning and he wasn't feeling well," a rep for the company that produces The Nate Berkus Show tells PEOPLE exclusively. "He powered through and then went straight to the hospital after that and they learned he had appendicitis."
Berkus, 39, had complained that he was under the weather, but didn't cancel his appearance. "He was in a lot of pain," adds the rep. "I don't think people realized how ill he was."
This will mean a schedule setback for the Oprah Winfrey disciple, whose own show debuted in September.
"He had to postpone tapings for now. He would have taped two shows today," according to the rep. "It's anticipated that he will be back next week."
For now, Berkus is "resting and he's expected to have an appendectomy," says the rep. "Doctors expect a quick recovery."