Alex Trebek has been diagnosed with stage 4 pancreatic cancer.

The longtime Jeopardy! host shared the news in a video posted to the trivia game show's official YouTube. Though the survival rate for this form of cancer is relatively low, Trebek reassured audiences that he fully intends to beat the disease and continue with his hosting role.

"[...] Just like 50,000 other people in the United States each year, this week I was diagnosed with stage 4 pancreatic cancer," the 78-year-old said. "Now normally, the prognosis for this is not very encouraging, but I'm going to fight this, and I'm going to keep working. And with the love and support of my family and friends and with the help of your prayers also, I plan to beat the low survival rate statistics for this disease. Truth told, I have to! Because under the terms of my contract, I have to host Jeopardy! for three more years! So help me. Keep the faith and we'll win. Well get it done. Thank you."

Sources told TMZ that Trebek will begin chemotherapy immediately. 

The Ontario native has been the face of Jeopardy! since 1984, and previously hosted shows like Music Hop, The Wizard of Odds, High Rollers, and CBS' Double Dare.

Trebek took medical leave from Jeopardy! in January 2018 after a severe fall resulted in blood clots on his brain. Nearly a year after he underwent surgery to remove the clots, Trebek told TMZ's Harvey Levin that he was seriously considering retirement. He even named his top replacement picks: Los Angeles Kings announcer Alex Faust, TCM host Ben Mankiewicz, and CNN analyst Laura Coates.

Trebek ended up renewing his contract through 2022.