The 40-year-old actor plays a chef in forthcoming movie Perfect Sense, and said that he was made to work in a professional kitchen beforehand to pick up some tips.
He told The Scotsman, 'I went along thinking maybe I could get away with sitting in the kitchen for a couple of hours watching people peel potatoes.
'But the guy running the place thought otherwise, and I spent a couple of days and nights doing steak tartare with raw egg on it.
'Don't ask me to cook anything though.'
The film was shot in Glasgow and Ewan said he managed to get around unnoticed by traveling by bike.
'I lived in a lovely mews house with cobblestones, went all over the place, and no-one noticed me. Maybe because they expected me to be in some big Mercedes or something,' he said.