Alex Trebek joked he has to beat his cancer diagnosis because he's under contract to host 'Jeopardy!' for three more years.

Alex Trebek, longtime host of “Jeopardy!,” revealed Wednesday afternoon that he has been diagnosed with stage 4 pancreatic cancer.

In a video message first posted on the show's YouTube page, Trebek said he was sharing the news to keep with his policy of being open and transparent with the show's fan base.

"I also wanted to prevent you from reading or hearing some overblown or inaccurate reports regarding my health," he explained from the show's set.

The 78-year-old went on to say that he, like 50,000 other people in the U.S. each year, was diagnosed with stage 4 pancreatic cancer this week.

"Now normally, the prognosis for this is not very encouraging, but I’m going to fight this, and I’m going to keep working," Trebek said.

Trebek brought some of his trademark humor to the announcement by joking that he plans to beat pancreatic cancer's low survival rate because he's under contract to host for three more years.

The longtime "Jeopardy!" host had hinted at retirement during an interview with TMZ’s Harvey Levin in July 2018, but quickly put away any rumors that he'd be stepping away soon by renewing his contract through 2022.

He has hosted nearly 8,000 episodes and holds a Guinness World Record for "Most Game Show Episodes Hosted by the Same Presenter." Born in Ontario, Trebek is one of the few celebrities to receive a star on both the Hollywood Walk of Fame and the Canadian Walk of Fame.

Trebek took a leave of absence in January 2018 after having surgery to remove blood clots from his brain.

The news of Trebek’s cancer diagnosis came as a shock to fans of the daily game show, which he has hosted since 1984.

Earlier this year during an appearance at 92nd Street Y, Trebek revealed who he thought would be a good fit to eventually take over his hosting gig. Some of the candidates he suggested included CNN's Laura Coates, LA Kings announcer Alex Faust and TCM’s Ben Mankiewicz, according to USA TODAY.

What is pancreatic cancer?

It's widely understood that pancreatic cancer is one of the deadliest cancers.

As Dr. Timothy J. Moynihan explained on the Mayo Clinic's website, even with aggressive treatment, the prognosis tends to be poor with a low survival rate.

Dr. Moynihan explained there are a number of factors that make treating the disease so difficult, including that early detection is uncommon and pancreatic cancer tends to spread quickly.

The American Cancer Society estimates that about 56,770 people will be diagnosed with pancreatic cancer in 2019 and about 45,750 people will die from it.

Supreme Court Justice Ruth Bader Ginsburg famously beat her pancreatic cancer diagnosis in 2009 after it was discovered at a very early stage.

Actor Patrick Swayze and singer Luciano Pavarotti both died from pancreatic cancer. Apple's Steve Jobs was diagnosed in 2003 with a rare form of pancreatic cancer called a neuroendocrine islet tumor.

Here is a transcript of Alex Trebek's full announcement: