'Jeopardy!' host Alex Trebek challenges viewers to guess whether he's wearing a wig or not

"Jeopardy!" host Alex Trebek is done keeping a stiff upper lip amid his battle with stage 4 pancreatic cancer.

In a May 1 conversation with "Good Morning America" host Robin Roberts, he discussed the mental impact of cancer, revealing the waves of "'deep, deep sadness" that have hit him since his diagnosis, which he announced in March.

This weekend, the Daytime Emmy winner got real about the physical effects of the disease on himself and his family during an interview with "CBS Sunday Morning" host Jane Pauley.

Trebek, 78, said his diagnosis is "very difficult in many ways" for his wife Jean Currivan.

"What I've discovered in all of this is that it's extremely difficult for the caregivers," the legendary host said. The couple have two adult children, Matthew and Emily.

Trebek revealed that "Jeopardy!" was still in production when doctors found a lump "the size of a small fist" in his abdomen. The tumor and the treatment regimen meant to shrink it caused debilitating stomach cramps both on- and off-camera. 

The TV icon announced to the world March 6, 2019, that he had been diagnosed with Stage 4 pancreatic cancer. Trebek says that although he's been told his chemo wig looks better than his real hair, he hopes to grow his own back over the summer hiatus.

“This got really bad," he told Pauley. "I was on the floor writhing in pain." At those moments, he said his pain level would jump "from a three to an 11." He added that there were times he would just barely make it back to his dressing room before the next wave of cramps hit.

Making matters worse, he said, was the frequency of the cramps –  which came "three or four times a day while we were taping – and the tight turnaround time between episodes.

He often had "15 minutes before the next show. So I got myself together and spasms of that kind usually last about 10 to 15 minutes. So all right, here we go again. ‘Anybody got any pain pills?’ And I don’t like taking pain pills. But –  so I – I got through it."

He was loath to cancel any episodes of the game show, which is currently enjoying peak ratings thanks to current champ James Holzhauer, whose record run resumes May 30. 

"The producers were very kind. They said, ‘Look, if you – 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.’ ”

Trebek admitted that he didn't fully realize how many people he has touched in the world until he revealed his cancer diagnosis in March.  

"I've had so many people send cards, letters, tweets, whatever, offering prayers," he said. "For 35 years I've enjoyed the success of the show, but I've never really thought about the impact the program was having on American viewers. And I've become part of their lives."

Trebek even joked that his chemotherapy-induced hair loss has opened the door for a new game for the show's fans.

“The challenge for 'Jeopardy!' viewers right now is to figure out, ‘Is that Alex’s real hair, or is that a full hairpiece?' " he cracked. "Which is it?"

In the case of the CBS interview, here's the answer, phrased the form of a question, "Jeopardy!" style: "What is a wig?"

Trebek added, "We have the summer months off. So hopefully my own hair will grow back. Because I like my own hair."

Contributing: Cydney Henderson

Alex Trebek gets real: 'Jeopardy!' on 'deep, deep sadness' he's facing in cancer battle