Houseguest

Houseguest is a 1995 comedy film starring Sinbad and Phil Hartman and directed by Randall Miller.

Although he knows nothing about dentistry, Franklin still manages to convince those around him that he is in fact Derek Bond, and his affable personality makes him popular with Youngs otherwise stuffy and rich neighbors and associates. Young has little time for his children and his wifes Kim Greist new frozen yogurt business, which gradually builds a gap between them, largely due to the demands of his bigoted, arrogant boss Mason Adams at the law firm where he works this leads to Franklin developing a bond with Youngs Goth daughter, helping her stand up to her cheating boyfriend, and his young son, who has aspirations of playing pro basketball. Young eventually stands up to his boss with Franklins support and quits the firm to be with his family. Meanwhile, the mob thugs threaten Franklins best friend, Larry Stan Shaw, into revealing his whereabouts, and Franklin asks him to pick him up. After he does so reluctantly, he sparks an argument with him over his lack of appreciation of friendship, causing him to realize that Young has been his friend all along. He returns to the Youngs house only to find that the mobsters have taken them hostage, and his true identity is revealed when the real Derek Bond finally shows up.After the mobsters take Franklin away, he manages to escape, losing them in a charity marathon, where he meets up with Young, who graciously decides to help him despite his charade, in return for helping bring his family closer together. Franklin reveals that he has an instant lottery ticket he purchased the previous day for a chance at a 1,000,000 cash prize spin on a Saturday night TV show, which he reluctantly gives up to the mobsters in exchange for the forgiveness of his debt. ........

Source: Wikipedia