Two of a Kind (1998)

"Two of a Kind" is a family comedy with a romantic twist. Kevin Burke is a science professor and single father who believes there is a scientific explanation for everything except how to control his scheming pre-teen daughters! Mary Kate and Ashley are twin sisters who are complete opposites. Mary Kate is a tomboy whose biggest interest is perfecting her curve ball; and Ashley is a straight-A student starting a boy-crazy phase. And then there's Carrie, a 26-year-old freshman in Kevin's seminar who has come late to college after exploring the world. Carrie is quirky, difficult, beautiful and quick to speak her mind, so when she answers Kevin's ad for a part-time nanny for the girls, he is convinced she's nothing but trouble. The girls think she is a dream-sitter come true and agree to put their differences aside and join forces to make a little chemistry between their by-the-book dad and the beautiful woman who seems to drive him crazy in all the right ways.