Jeopardy!” host Alex Trebek’s wife was the first person to spot this one symptom in her husband, which later led to his stage 4 pancreatic cancer diagnosis.

In a blog post, Jean, 56, described the moment she noticed something “off” about Trebek, 80, on a vacation in Israel.

“We’d gone to Israel to visit the sites of the Holy Land in December 2018, taking our son and daughter, Matthew and Emily, then 27 and 24,” she began in a personal essay on Guideposts.

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Alex Trebek and Jean Currivan Trebek attend the 47th AFI Life Achievement Award honoring Denzel Washington (Michael Kovac/Getty Images for AFI)

Jean recalled, “We’d finished dinner one night, and I looked across the table at Alex. His coloring seemed off. ‘You feeling okay?’ I asked.”

“‘I’m good,’” she recalled the “Jeopardy!” host telling her. “Alex is not one to complain. But he admitted that he was having some stomach pains. I figured, okay, we were in a different country. Maybe it was something he ate."

However, when the couple returned to California, she reflected, “Things were still not right.”

‘JEOPARDY!’ HOST ALEX TREBEK SAYS WIFE JEAN ‘KEPT ME ALIVE’ DURING CANCER BATTLE

Alex Trebek revealed that his wife, Jean Currivan, has been the best support he's had throughout his cancer battle. (Michael Kovac/Getty Images for AFI)

“His doctor ran some tests, then some more. We weren’t so worried that we canceled a trip to New York,” Jean admitted.

The couple then received a concerning call from Trebek’s doctor, which caused them to end their trip early.

“It was there, in our hotel, that we got a call from his doctor. ‘We need to see you as soon as you get back from your trip. We have some concerns,’” the mother of two recalled.

Jean continued: “He went in for a CT scan—all of this at Cedars-Sinai in Los Angeles, not far from our house. The doctor called back within hours. ‘We need to talk,’ he said. We went back and got the news. Pancreatic cancer with a tumor that had spread to the soft lining of his stomach. Stage IV.”

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TV personality Alex Trebek and his wife Jean attend the 2014 AFI Life Achievement Award: A Tribute to Jane Fonda (Getty)

The real estate project manager revealed she was initially devastated by the diagnosis.

“I wondered then how long we had,” Jean confessed. “More than a year and a half later, we’re still at it, every day a gift.”

Trebek’s wife also admitted to having days where she is “really sad and angry,” but she tries to always look on the bright side using her faith.

“With each passing day, I have found so much to be grateful for. Alex’s work. Our kids, our friends, a sunset, a flower blooming in our garden,” Jean wrote.

She added: “This didn’t have to be a death sentence. It could be a life sentence. A constant reminder of how precious life is. The smallest things that I once took for granted now carry more meaning. I think that is how God keeps us in the moment. He focuses us with grace.”

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Alex Trebek poses with the Daytime Emmy Award for Outstanding Game Show Host (Gregg DeGuire/Getty Images)

Trebek received his cancer diagnosis in March 2019. Despite the devastating news, the couple’s love for each other has endured.

The longtime game show host opened up about his marriage in a memoir titled “The Answer Is… Reflections On My Life,” which is out now. In the book, the 80-year-old described how the 56-year-old has been his rock during his stage 4 pancreatic cancer diagnosis.

“She’s kept me alive,” the host told People magazine last month. “If it weren’t for Jean, I’d had put myself out of this a long time ago.”

In his memoir, People said, he wrote: “I’ve got [a] framed image. Jeanie gave it to me. It’s a line from our favorite movie, ‘Wuthering Heights.’ ‘Whatever our souls are made of, yours and mine are the same.’ That’s the way I look at our relationship. We are one soul in two bodies.”

Alex Trebek attends 'Who is Alex Trebek? Celebrating 35 seasons of Jeopardy!'  (Santiago Felipe/Getty Images)

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Trebek first met Jean through a mutual friend in 1988 when he was 47 years old. At the time, Trebek had been hosting “Jeopardy!” for just four years. According to the outlet, he was newly single after his divorce from his first wife, businesswoman Elaine Callei. As for Jean, who was 23 at the time, she was doing part-time bookkeeping for one of Trebek’s friends.

The couple got married in 1990.

FOX News  Stephanie Nolasco contributed to this report.