Alex Trebek has just been diagnosed with stage 4 pancreatic cancer, but not only will he finish out this season of “Jeopardy!” — he has no plans to retire … TMZ has learned.

Sources connected to Trebek tell us, the TV icon was just informed of the diagnosis. He recorded a video message announcing his diagnosis.

We’re told Alex’s will finish out the current season of “Jeopardy!.” In fact, he says he’s vowing to keep working and he’s bravely upbeat. In the video, he says he plans to beat cancer.

Sources connected to the legendary host tell us he will immediately begin chemo.

Alex even managed to add some humor in his message, pointing out his contract calls for him to host for 3 more years — and that’s exactly what he intends to do.