Clyde bellies up to the bar at the Franklin Fountain, the throwback ice-cream emporium in Old City, his paws on the marble counter, poised to take a triple-dip sundae in a single lick.

Clyde ignores all questions about his Marley & Me costars Owen Wilson and Jennifer Aniston, although it is a widely circulated rumor that he got, um, overly friendly with Jen's favorite sweater. Clyde is, in every meaning of the word, a dog.

It required six actors (including Cate Blanchett and Heath Ledger) to capture the many facets of Bob Dylan in I'm Not There. It required 16 more creatures - 22 in all! - to embody all the moods and manias of Marley, who promises to be the most beloved movie canine since Lassie.

There is "clearance puppy" Marley, pouncing Marley, mature Marley, and Old Yeller Marley, all of them famished.

Of the many canines that impersonated the Grogan family dog, the most cinegenic might be 4-year-old Clyde, a 75-pound biscuit-hued Labrador with coffee-colored smudges on his muzzle. His heroic profile rivals that of John Barrymore and Scooby-Doo put together.

Clyde, who's been traveling the U.S. in recent weeks, spreading the gospel according to Labrador, has already scarfed down three Geno's cheesesteaks and he's raring for dessert. The Franklin Fountain has prepared a dog-friendly soy ice cream sundae with peanut butter sauce, but Clyde's trainer, Mathilde DeCagny, does not let him indulge in sweets.

Still, Clyde seems to enjoy almost eating a sundae as much as he would actually eating one. For a yellow Lab, a breed that's essentially 12 ounces of nose wrapped in 74 pounds of fur, a breed built for smelling, hunting, retrieving and eating, that's acting.

Every dog has his day, and today it is Clyde's. Let other pups go to obedience school; Clyde matriculated at the DeCagny Disobedience Academy. She trained him to do what most Labs do instinctively: Chew, Charge and Drool.

"His job was to destroy everything that came into his path," says the trainer, whose other famous working dog is Moose, the Jack Russell who played Eddie on Frasier.

Clyde ignores all questions about salary. DeCagny says only that "his rewards are treats, toys, tennis balls." And about that brush with Aniston's sweater?

"He grabbed it; he didn't eat it," DeCagny swears.

Contact movie critic Carrie Rickey at 215-854-5402 or crickey@phillynews.com.

Read her blog, "Flickgrrl," at http://www.philly.com/philly/blogs/flickgrrl.