Nicholas Art plays a brat and Scarlett Johansson is the nanny in "The Nanny Diaries."

Having set the standard for contemporary chick-lit adaptations, "The Devil Wears Prada" is a tough act to follow. The clothes, the attitude, the scene-stealing, Oscar-nominated work from Meryl Streep — anything would pale by comparison.

But "The Nanny Diaries" especially does, and it might have seemed like solid, sufficiently mindless summer entertainment otherwise.

Based on the 2002 guilty-pleasure read by former New York nannies Emma McLaughlin and Nicola Kraus, the film remains true to the book with a few tweaks here and there, until it loses its bite and suddenly goes all soft and gushy at the end.

In rare regular-person mode, the va-va-voomy Johansson capably stars as Annie Braddock, a young woman who's unsure of what to do with her life after college. She wants to be an anthropologist, while her more practical mother (Donna Murphy) wants her to transcend her working-class New Jersey upbringing with a career in finance.

After a miserable job interview, Annie literally stumbles into a nanny gig for a posh couple on Manhattan's Upper East Side (Linney and Giamatti) and their bratty son, Grayer (Nicholas Reese Art). To protect the guilty, the couple has been dubbed Mr. and Mrs. X in the both the book and the movie.

Mrs. X seems nice enough when they first cross paths, and Annie figures, why not live a luxurious life while I work through my post-academic agita? But Mom quickly reveals herself to be a control freak, with very specific ideas about how every moment of Grayer's days should be occupied (the Guggenheim, organic snacks and nothing that involves public transit or the West Side). Grayer is, of course, a tiny terror until the moment he does an abrupt about-face and becomes a playful, loving angel.At the same time, Mrs. X is too busy shopping and lunching and planning fundraisers to take part in any of these activities herself, and Mr. X is so consumed with conquering the corporate world, he barely acknowledges that he has a wife and a son.Similar to "Prada," increasingly capricious demands and explosive pratfalls ensue. Annie, who's referred to throughout as the more generic Nanny, repeatedly makes a fool of herself in front of the cute boy upstairs, known only as Harvard Hottie (Chris Evans from the "Fantastic Four" movies). And her sassy best friend (an underused Alicia Keys) is relegated to looking on disapprovingly at the mess Annie has gotten herself into.Anyone could have directed this material; "The Nanny Diaries" wasn't exactly great literature. So the real letdown comes from knowing that the film is from Shari Springer Berman and Robert Pulcini, the husband-and-wife writing-directing team behind the thrillingly inventive "American Splendor," which also starred Giamatti as comic-book writer Harvey Pekar.While Berman and Pulcini vividly depict a glossy New York, a city they both clearly know well, they don't provide any fresh or nuanced insights into the class disparities that exist there: "Dear Diary, The rich are different. The end."