The real star of the Owen Wilson and Jennifer Aniston’s film Marley & Me is a three-year-old dog named Clyde. As one of 21 dogs playing the title role in the film — out on DVD today — Clyde steals the show.

The subtitle of John Grogan’s best-selling book, upon which the movie is based, is Life and Love with the World’s Worst Dog, which is a lot for any one dog to live up to. For Clyde’s part, he had to tear apart pillows, knock down toddlers, jump into pools on command and hump a lot of legs.

Mathilde DeCagny had the difficult task of training the dog to appear as if he wasn’t trained at all.

“It’s training, and it’s fun because you take a dog and make him even more of a dog,” she says with a subtle French accent.

Clyde is constantly wagging his tail when I meet him and DeCagny at the Boston Public Library, where a group of students had come to see the dog. She says she will eventually have to train Clyde to be a good dog, but not yet.

“I was asked to leave him this way for promotional purposes,”?she says as the Lab tugs at her leash, eager to socialize more with his audience. “He’s also going to be the dog he is, and I’m going to work with that, because I don’t want to break his spirit. I need to calm him down a little bit, but he’s always going to be a loving, spirited dog.”

Clyde, who DeCagny says “did 80 per cent” of the film, is indeed a loving, spirited dog. At one point in the interview, she gives an example of the command that would prompt the pooch to perform his tricks.

“Go get ’em Clyde,” she says, and with that, the dog jumps up on this reporter’s lap and licks his face, to the laughter of the school children in attendance. Never has an interview subject been so affectionate.

DeCagny has a lot of experience with dogs. She worked on the show Frasier for 11 years, and trained and took care of the two Jack Russell terriers who played Eddie. She also worked with the same dogs in My Dog Skip.

So what’s next for Clyde?

“He’s not going to have another big feature like this, because once they have such a permanent part, they get typecast,” she says. “He belongs to the company that I work for, which is called Birds and Animals Unlimited, but he is with me ... He’ll just be my dog.”