This is a comedy - lead character is male, and I believe it was set in Britain. There exists a TV show (in the fictional world of the movie) where people can set up their friends. The "victim" responds to some "random" event which sets off a scripted series of events which are filmed and designed to provide excitement.
From what I remember: the man answers a phone call, breaks up a fight between a couple in a home, and somehow becomes involved with real criminals whilst believing it is all scripted and part of the show.
I believe this movie was released in the 1990's.