Renee Zellweger has a face that looks like it's about to pop. Her famously pursed lips barely constrain an energy that, if uncorked, threatens to launch her off in all sorts of interesting directions.

It's a face that hints at the movie roles that work best for her - where vital force bangs up against social convention. Whether its Bridget Jones trying to master the subtleties of single life in London or Ruby Thewes insisting on her spelling prowess in "Cold Mountain," Zellweger is a lot of fun to watch while putting propriety through the wringer.

In "Miss Potter," Zellweger may have found her soul mate. As Beatrix Potter, the legendary author of "The Tale of Peter Rabbit" and other children's books, Zellweger joins forces with a character who assaulted the limited options for women in the Victorian era armed only with what publishers dismissively referred to as a "bunny book."

"Miss Potter" opens with Beatrix presenting her book to yet another publisher struggling to look politely interested. Just as she is steeling herself for a carefully worded rejection, the publisher agrees to take on her book. It turns out that he has a younger brother who has been badgering him to be allowed to join the firm. A book that will be a sure-fire failure seems like a great way to discourage his ambitions.

But the publisher has underestimated the subversive power of innocence. The young brother, Norman Warne (Ewan McGregor), shows up at Beatrix's doorstep as determined to carve a success out of this project as she is.

As an actor Ewan McGregor has an uneven resume. After a flashy start in "Trainspotting," McGregor has often lacked the necessary heft for his roles. He can come across as Tom Cruise Lite - a market niche no actor should aspire to. But "Miss Potter" is a lucky break for him as well. Norman is newly acquainted to his own ambition - like Potter he is untested but determined - and McGregor captures his essence. When Norman exclaims, "We shall give them a bunny book to conjure with!" you're not sure whether to laugh or cheer.

"Miss Potter" is a revolution of small gestures in close quarters, in other words a family drama. Mainly it is about Beatrix frustrating the well-planned expectations of her parents and Norman confounding the business wisdom of his older brothers-and the two of them falling in love along the way.

While "Miss Potter" has aspirations to inspire-a Rocky Balboa for budding bookworms-it, like Potter's stories, wins you over with charm and sly wit. The families of Beatrix and Norman are populated with a colorful collection of characters who to differing degrees are either impressed or appalled by Beatrix's determination to become an author, but, as families do, gather around her when tragedy strikes.

Barbara Flynn is terrific as Beatrix's mother, Helen, a self appointed bulwark of Victorian sensibility. Her determination to shoehorn Beatrix into a respectable life includes saddling her with a chaperone in the person of the comically long-suffering Miss Wiggin (Matyelok Gibbs).

"Miss Potter" rambles a bit, trying to build a narrative fence around a complex life, and history has already told us that she finds her success as an author. But the intricate maze of love, family, and Victorian mores makes the journey worth watching.

If you are a Zellweger fan or just like British costume drama, "Miss Potter" is a charmer.

Directed by Chris Noonan

Rated: PG

(Three Stars)