But it’s as Jiff that Murphy gets his biggest laughs. Here is a man so grateful to be in a film, so disbelieving that he has been singled out for stardom, that he dutifully risks his life to walk across a busy expressway. Murphy shows here, as he did in “The Nutty Professor” and on “Saturday Night Live,” a gift for creating new characters out of familiar materials. Yes, Jiff looks like Kit (that’s why he got the job as a double), but the person inside is completely fresh and new, and has his own personality and appeal. Although Murphy is not usually referred to as a great actor (and comedians are never taken as seriously as they should be), how many other actors, however distinguished, could create Jiff out of whole cloth and make him such a convincing and funny original? Martin is also at the top of his form, especially in an early scene where he pitches his project to a powerful studio executive (Robert Downey Jr.). Martin steals a suit and a car to make an impressive entrance at the restaurant where Downey is having a power lunch, but undercuts the effect a little by ripping out the car phone and trying to use it like a cell phone–staging a fake call for Downey to overhear. Downey handles this scene perfectly, right down to his subdued double-take when he sees the cord dangling from the end of the phone. His performance is based on the truth that strange and desperate pitches are lobbed at studio suits every day, some of them no more bizarre than this one. Instead of overreacting to Martin’s craziness, Downey plays the scene to humor this guy
— Read on www.rogerebert.com/reviews/bowfinger-1999