The David Tennant Treat 4 Today is from David Tennant's 1998 movie LA Without A Map.
David plays a British writer called Richard who sets off from Bradford, Yorkshire to try his luck in Hollywood. It's a comedy and shows David's great comic timing throughout the film.
This film co-starred Johnny Depp playing himself (in posters) and according to IMDB he did not make any money from his cameo role.
This clip is very funny but be warned that it features VERY strong language.