Alex Trebek, longtime host of "Jeopardy!," is opening up about what it was like to return to work while battling stage 4 pancreatic cancer. 

Trebek said in an interview for "CBS Sunday Morning" that early on in his cancer treatment he would suffer excruciating stomach cramps. 

"This got really bad. I was on the floor writhing in pain. It went from a 3 to an 11. And I just couldn't believe, I didn't know what was happening. And it happened three or four times a day while we were taping. So, that was a little rough on me," the game show host described to "Sunday Morning" host Jane Pauley in an interview set to air May 12. 

Trebek announced his diagnosis of Stage 4 pancreatic cancer in March. Since then, fans from all over have shared with him their own cancer battles, prayers and well wishes.

Trebek also recalled one occasion where they taped a show and he just barely made it to his dressing room before writhing and crying in pain. 

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He also explained that the cancer treatment led to him now wearing a hairpiece.

"This is not the real me," Trebek said, in reference to his hair during the interview. "But 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. 'Cause I like my own hair!"