Simon Pegg squeezes into some very small shorts for this cheeky offering directed by former Friends star David Schwimmer (with whom he co-starred in Big Nothing). As titular "fatboy" Dennis, Pegg looks doomed to failure when he signs up for a marathon to prove his love to former flame Libby (Thandie Newton). She's tough to please though, which is understandable as Dennis left her pregnant at the altar five years earlier. Schwimmer gets plenty of comedy mileage out of Dennis's shortcomings - including the inevitable locker-room confrontation with Libby's hunky new fiancé (Hank Azaria). A few of the gags are obvious and lazy, but overall there's a good balance of laughs and emotion, with Pegg managing to be endearing even as he molests a shop mannequin. The last leg of his journey (a race across London), while a bit contrived, will surely raise some hearty cheers.

Five years after jilting his pregnant fiancée on their wedding day, out-of-shape Dennis decides to run a marathon to win her back.