Matt Jackson, who was competing in his 13th game on "Jeopardy!" this week, made an admission during one of the commercial breaks that actually cost him $1,600.
Jackson, who WJLA-TV reports is a 23-year-old paralegal from Washington, D.C., was initially awarded for answering a question correctly, before coming clean that he had really said the wrong thing.
Host Alex Trebek broke the news just before the "Double Jeopardy" round.
"Kudos to our champion Matt Jackson, who during the commercial break informed our judges that in the two-word 'A' category a few minutes ago, he did not mispronounce 'au,' the French word for 'au.' He meant to say al, a-l," Trebek said. "So we are deducting $1,600 from him."
Watch the moment of honesty:
In the end, Jackson's winning streak ended Wednesday night, but he still walked away with $411,612, according to WJLA. He will return to the show for the "Tournament of Champions" in November.
"It is pretty hard to wrap my mind around," Jackson told the news station. "While I was in the middle of playing, I really didn't want to think of it as money because it could mess with my ability to make wagers and take calculated risks. So it's still hard to believe it will be actual prize money coming my way soon."