Longtime "Jeopardy!" host Alex Trebek revealed in a YouTube video on this day in history, Wednesday, March 6, 2019, that he had been diagnosed with stage 4 pancreatic cancer.

Trebek, age 78 at the time, said he learned of the condition that week, as he explained in a video that shocked millions of people who had watched and followed the popular program under his guidance. 

"Now, normally, the prognosis for this [pancreatic cancer] is not very encouraging, but I’m going to fight this, and I’m going to keep working," he announced in the video.

ON THIS DAY IN HISTORY, MARCH 5, 1966, PATRIOTIC SONG ‘THE BALLAD OF THE GREEN BERETS’ HITS NO. 1

"And with the love and support of my family and friends and with the help of your prayers also," he also said, "I plan to beat the low survival rate statistics for this disease."

Then, Trebek joked that he'd have to recover in order to fulfill the TV hosting duties he was contracted to finish.

"Truth told, I have to! Because under the terms of my contract, I have to host 'Jeopardy!' for three more years!" he said. 

"So help me. Keep the faith and we’ll win. We’ll get it done. Thank you."

He offered the update on his health, he said, to be "open and transparent" with fans of the TV show.

ON THIS DAY IN HISTORY, MARCH 4, 1952, RONALD REAGAN MARRIES NANCY DAVIS IN CHURCH CEREMONY

He continued to offer fans and followers updates on his health as time passed and as he underwent treatment.

He vowed to continue hosting and doing the job that he said he loved for as long as possible.

He also hinted, however, that he was coming to terms with the idea that he might need to stop treatment in order salvage his quality of life. 

Trebek also shared with followers, "I’m going to stick with this current protocol, then that’s it. If it doesn’t work I’ll probably stop treatment," he wrote. 

"Quality of life was an important consideration."

However, he later assuaged those fears with a follow-up statement in July.

"That quote from [his] book was written BEFORE my current regimen, and I was going through some bad times," Trebek explained. 

"My current numbers are very good, but we will have to be patient with this new immunotherapy program that I am on," he also said. 

"But if we were to stop being successful, I would return to my previous chemo treatment — NOT stop all treatment."

Trebek would pass away of the disease on Nov. 8, 2020.

"This is an enormous loss for the ‘Jeopardy!’ staff, crew and all of Alex’s millions of fans," Mike Richards, then executive producer of the program, said in a statement to Fox News at the time. 

ALEX TREBEK ESTATE SALE BRINGS ‘JEOPARDY!’ FANS TO LATE STAR'S FORMER HOME

"He was a legend of the industry that we were all lucky to watch night after night for 37 years. Working beside him for the past year and a half as he heroically continued to host ‘Jeopardy!’ was an incredible honor … His constant desire to learn, his kindness, and his professionalism will be with all of us forever."

Trebek had hosted the "Jeopardy!" program since 1984 — for 37 seasons in all. He presided over more than 8,000 episodes. 

During his career, he received the Daytime Emmy Award for Outstanding Game Show Host eight times for his work on "Jeopardy!"

He routinely talked about how much he enjoyed hosting the popular game show and even credited fans with helping him throughout his treatment. 

When production halted due to the COVID-19 pandemic, he was one of the loudest voices in championing for the show to come back safely.

Trebek was born in Greater Sudbury, Canada, becoming a naturalized American citizen in 1998.

He passed away in Los Angeles after his 20-month battle with pancreatic cancer.

Following Trebek's death, a series of guest hosts filled in for him for his final "Jeopardy!" season.

Mayim Bialik and Ken Jennings, in July 2022, were announced as his co-successors as permanent hosts after they took turns for the show's 38th season. 

CLICK HERE TO SIGN UP FOR OUR LIFESTYLE NEWSLETTER

Prior to that, a string of guest hosts filled in temporarily. 

Bryan Robinson of Fox News Digital, as well as Elizabeth Zwirz and Tyler McCarthy, contributed to this report.