Most Hollywood starlets would give just about anything - and they frequently do - for the secret of stardom. But it's not the commodity it once was. So when a young actress arrives on the Hollywood scene with what seem to be all the ingredients for stardom, it's no wonder she causes a stir. Kate Jackson has caused a stir.

It's a subtle awakening of the inbred acting community that usually acknowledges only the most vividly vocal. But everything about the actress from Birmingham, Alabama is subtle. Her personality rings like a deep, full-bodied chuckle rather than a brassy guffaw. Her screen presence on the ABC-TV series The Rookies is amiable. And her appearance is so understated and classy you tend to forget you're sitting with one of Hollywood's true beauties. It's a fact not overlooked by the various fashion magazines that have sent emissaries to town to request her presence in their pages. (Kate started her career in New York a few years ago as a model, but abandoned it because "that's the hardest work in the world.") Nor have Hollywood's most eligible bachelors overlooked her. When she's on the arm of Paramount Pictures' charming production chief Bob Evans (last married to Ali MacGraw) or that of handsome young Edward Albert (recently shown the door by Liza Minnelli), Kate's personal life seems to garner its own particular notices.

She has the kind of charisma that in another era meant instant stardom. Perhaps it still does, but Kate finds herself confounded. And amused.

"I'll never quite understand it," she admits. "I don't know why people pay so much attention to me."

If she were pulling outrageous publicity stunts, or living the kind of Hollywood razzle-dazzle that some actresses do, the attention would seem natural. But Kate isn't your average headline-hungry starlet. Nor has she appeared in so many major theatrical projects that her continued screen exposure creates interest.

Despite her continuing role on the popular Rookies series and the fan letters tumbling in, her idea of a good life doesn't mean hiding behind a pair of sunglasses or curling up with a toddy and a good, leave-the-world-alone philosophy.

Skiing is her passion and she's familiar with the slopes from California to Vermont to Europe. Her ski buddies most often are series co-stars Michael Ontkean and Sam Melville.

She is prouder of her role on The Rookies and in the ABC movie Killer Bees than her earlier film efforts. Her first series was the New York-based soap opera Dark Shadows, an experience that taught her a large fan following doesn't always mean a quality show. Her appearance in the exploitative House of Dark Shadows movie brings a grimace and a chuckle from her. Her other films, including Limbo, weren't all that well received. She has yet to land that "super movie."

But her star continues to rise - thanks to her ever-growing role on The Rookies, and the beauty that seems to sparkle from within.