Just when you were ready to write off Renee Zellweger to the middle-brow rom-coms and period dramas where former Oscar winners go when they approach middle age, along comes a movie like “My One and Only” to remind you of what a likable, indefatigable actress she can be.

The film, spawned during a meeting in which George Hamilton told the late Merv Griffin about his unusual childhood, has kicked around Hollywood in various stages of development for 10 years.

It finally got made in what passes today for the independent film circuit: It still cost millions of dollars and stars famous people, but has few marketing dollars behind it.

Zellweger stars as Ann Deveraux, an aging but still-scrappy Southern belle who grabs her two sons – the prissy Robbie (Mark Rendall) and Hamilton stand-in George (Logan Lerman) – and leaves her cheating husband (Kevin Bacon) in the act with another woman in their New York apartment in 1953.

Ann leaves in a Cadillac with two goals in mind: getting somewhere west of here, and a new husband.

As she and her sons drive across country, they encounter a series of ex-boyfriends and potential suitors (played by, among others, Eric McCormack, Chris Noth and Steven Weber). They also fall into all kinds of misadventure. Ann gets arrested; later, she gets robbed.

The film’s relentlessly nostalgic, bouncy tone, however, assures that all will end well, and even the resentment felt by Ann’s sons will be smoothed over.

“My One and Only” isn’t exactly memorable, but this little, personable movie is a fine showcase for Zellweger’s talents and a paean to the sort of mid-1950s America best remembered in Norman Rockwell paintings.