The Brit, who fronts his reality cookery show Hell's Kitchen in the U.S. and U.K., was showing the comedienne-turned-TV presenter how to slice vegetables for a stir fry when his knife slipped, leaving him with blood dripping from the deep cut on his finger.
Laughing off the mishap, Ramsay said, "I wasn't concentrating. I haven't cut myself this big in 10 years! (I cut my finger) under the nail. I took the nail off."
The pre-recorded show aired in the U.S. on Tuesday (23Feb10).