In his first in-home interview since going public with his battle with pancreatic cancer, Alex Trebek discussed the painful struggles he faced – sometimes during a 15-minute break in between Jeopardy tapings – after learning of his diagnosis.

In an interview with CBS Sunday Morning, Trebek, 78, said that he had been diagnosed with stage four pancreatic cancer while Jeopardy was still in production when his doctors discovered a "small fist" sized lump inside his abdomen.

Still, Trebek, who has filmed nearly 8,000 episodes, was adamant that the show went on, despite sometimes barely making it to his dressing room to "[writhe] in pain."

“This got really bad. I was on the floor writhing in pain. It went from a three to an 11. And I just couldn’t believe. I didn’t know what was happening,” Trebek says. “And it happened three or four times a day while we were taping. So that was a little – little rough on me.”

Trebek told CBS that he would take the 15-minute breaks in between filming episodes of the show, which films a week's worth of episodes in one day, to "get myself together," adding that his spasms lasted about ten to 15 minutes.

"The producers were very kind," Trebek said. "They said, ‘Look, if you don’t want to do the show, we’ll just cancel taping.’ I said, ‘No. We’re here. We’re doing the shows.’”

The unflappable host, upon learning his diagnosis, immediately underwent chemotherapy, and he admitted that he's curious if eagle-eyed fans will notice he had to wear a hairpiece.

"On air I’m told that there were times – when the hairpiece looked better than my real hair. So we’ll see how people react to that. We have the summer months off. So hopefully my own hair will grow back. Because I like my own hair,” Trebek says.

Trebek's full interview will air at 9 a.m. EST on May 12 on CBS Sunday Morning.

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