The cast was surprised to learn that Helen Mirren is really a man.

Come on, you know you've always wanted to see Julie Walters naked, you cheeky perv.

Calendar Girls tells the mostly true story of a bunch of respectable, middle-aged Englishwomen who decide to get their kit off for a good cause. Our main characters are Chris (Helen Mirren) and Annie (Julie Walters), best friends who smirk and giggle their way through meetings of the local chapter of the Women's Institute, featuring topics like "The History of Broccoli" and vacation slide shows that begin with, "It all started when I called the travel agent." After Annie's husband dies of leukemia, Chris comes up with an idea to raise money for a new couch for the relative's room at the cancer ward. Rather than the WI's usual calendar featuring the local scenery, they'll put out a girlie calendar, with the WI members as the girls.

"Yes, but has she been nominated for an Oscar?"

A few of the ladies are eager to sign up. Most need a little more convincing. (Some of these women have never even let their husbands see them naked, for crying out loud. How very Victorian!) There's resistance, of course, from the stodgy leadership. But eventually, the photos are tastefully shot by a local amateur photographer and the calendar is published. Instead of the small local splash they were hoping for, it quickly becomes an international sensation and the women are soon strolling through their Yorkshire village with gaggles of reporters in tow, and fielding calls from Jay Leno.

Calendar Girls is a charming trifle, as fluffy and sweet as meringue, whose only real flaw is a severe conflict shortage. Screenwriters Tim Firth and Juliette Towhidi attempt to heighten the drama a bit with a falling out between the friends and some marital angst for Chris. These storylines are okay, but too easily resolved to have any real weight. I'm not sure what I would suggest - the women foil an international drug cartel? murder at the photo shoot? nah, I just don't see it - but there's really not much story here and that gets a little old.

On the plus side, the movie is sharp and funny with a refreshingly straightforward and breezy style. Director Nigel Cole keeps things moving at a sprightly pace and has a nice, light touch with the comic as well as the sad parts of the story. The illness and death of Annie's husband are handled sweetly and sensitively without turning maudlin.

Sure they look happy. That cup? Full of gin!

The cast is superb and clearly having a fine time, and the two leads, in particular, are perfectly cast. Walters is poignant and funny. Her grief and anger over her husband's death are apparent on her expressive face without ever being overdone and she manages to play the sweet, brave widow without turning into a cloying saint. As for Mirren, after years of seeing her stern-faced and rigid in heavier fare like Gosford Park and the "Prime Suspect" series, it was a delight just to see her laugh.

Calendar Girls may not have much going for it in the way of plot, but there are plenty of laugh-out-loud moments and I predict you'll leave the theater smiling. And if you find yourself at odd moments thinking about Helen Mirren making apple cider, well, that's between you and your therapist.

Gorilla Pants rating: 2.5 out of 4 bananas