Updated: April 07, 2018

Fast Fact:

One of the worst-kept secrets in Hollywood is that the role of the most famous female dog in the world has always been played by a male dog.

(CBS) It's a brand-new telling of a story that's as old as the hills: the love of a dog for her family — a dog who will do anything to come back home. And come September, a new generation is poised to take this dog into their hearts.

Yes, it's time to get out your hankies, because Lassie is back. In an era of action-packed, computer-animated children's movies, the very idea of Lassie seems downright old-fashioned, says CBS News correspondent Cynthia Bowers.

But according to her biggest fans, it was Lassie who literally defined today's image of the modern family dog.

Veterinarian Jeff Werber has been traveling across the country with Lassie on a five-month publicity blitz, promoting the film and a new line of Lassie products. Yet behind all the marketing, Werber says there's some real magic at work.

"There is nothing like the relationship that we can have with our animals and animals with us," he says. "And until you experience it, you can't even describe it. And what I'm hoping is that if this Lassie rebirth is going to do is let everybody see and experience and hopefully experience for themselves that amazing, wonderful bond."

The world first met lassie in 1938, in the pages of the Saturday Evening Post.

The short story "Lassie Come Home" was written by Eric Knight as a Christmas tale. Knight later expanded the work into a novel, drawing on his deep affection for his pet collie, Toots, and for the people of his native Yorkshire, England.

The novel became a best-seller and soon inspired the classic 1943 film. A runaway hit for MGM, "Lassie Come Home" propelled its star into the big time, not to mention her 11-year-old castmate Elizabeth Taylor.

The film was followed by six decades of sequels on the big and small screens — transporting Lassie from the Yorkshire moors to the California hills.

Along the way, a formula evolved: whenever her boy faces danger, Lassie is there to save the day. You may have heard the expression, "Timmy's in the well" — shorthand for a typical Lassie dilemma.

The storyline was even parodied in a recent ad for GE, featuring a computer-enhanced canine.

But for true Lassie loyalists, only the real dog will do.

Joan Neidhardt of Abingdon, Md., and Cathy Schmidt of Woodland Hills, Calif., are co-founders of Colliewood — Lassie's fan club and Website.

"To a Lassie fan, that's not just a dog," Neidhardt says. "To younger generations that are just starting out, it's a fictional character; it's a book; it's a movie. It's this beautiful dog onscreen. To the people that have come to know and love Lassie over the years, the actual, living dog is a treasure."