And this weekend, that question is answered in the new, heartwarming family film, "Because of Winn Dixie," which is based on the best-selling children's book of the same name.
It stars the delightful AnnaSophia Robb, 11, as India Opal, who is in need of a best friend.
She gets to adopt the dog, who's named for the Winn-Dixie supermarket where she found him. The bond between the girl and her special companion, who's played by a dog named Laiko in real life, brings together the people in a small Florida town, and heals her troubled relationship with her father.
On The Early Show Thursday, Robb tells co-anchor Hannah Storm Laiko was a pleasure to work with: not only expressive, but "sweet, too. He is always so calm, and he hangs around and loves to be rubbed."
Robb has a Maltese at home.
She says she found acting with a dog in most scenes "great. I love working with dogs. I mean, they're so lovable. You always have a best friend on the set. And sometimes, he could be a little stubborn at times, but most of the time he was good."
She says there was a wonderful, unscripted moment in a scene where she bathes Winn Dixie in which the dog runs away.
But that dog, she reveals, was the other one who played Winn Dixie, one named Scott, who "didn't like the water," Robb says.
It was at about that point in the interview where Laiko decided to walk off the set, leaving Robb and Storm to carry on alone.
Robb also stars in the film, "Samantha: An American Girl Holiday," and says other kids are now starting to recognize her.
So, says Robb, this is all a dream come true for her.
She adds that she asked her mother when she was only 3 if she could have an agent, and her mother "wouldn't let me do it. …I kept on begging her, and finally, at 8, she said, 'OK, I'll find you an agent.' "
Robb is also set to appear this summer in "Charlie and the Chocolate Factory" which, she stresses, isn't a remake of the Gene Wilder movie, "Willa Wonka and the Chocolate Factory" film. It's an adaptation of the classic book by Roald Dahl.