By Stacy Jenel Smith

When it comes to exciting young actresses, this fall TV season is bringing us a bountiful harvest. By May, some will be out of the picture, some will be hanging in there as barely-knowns - and a few will have seen their stars rise markedly. Following are three very different gals who are definitely worth watching:

THE BAD GIRL
Adrianne Palicki is about to happen on the show business scene.

At least, that is the expectation of the 23-year-old actress' fans - many of whom spotted her on UPN's "South Beach" as feisty model Brianna, or "Smallville" as Kara, the super-powered girl, who first appeared in the altogether, a'tapping on Clark Kent's window -- who've already set up appreciation web sites.

And that is the expectation of NBC, which has made sure to show off the beautiful blond, who is playing that very naughty vixen, Tyra, in its soon-to-debut series spinoff version of "Friday Night Lights."

And that is the expectation of many critics as well, since the show is considered one of the more promising among this year's new fall entries and, well, Tyra is the kind of character who makes stars out of unknowns.

Toledo, Ohio-born Palicki already seems to have been placed into the teen temptress slot, having been hired to play an evil siren in an attempted "Smallville" spinoff, the Aquaman-centric "Mercy Reef.."

"Playing these characters, you get the fun lines, you get to go outside of yourself," says Adrianne.

So, does that mean Adrianne is not naughty in real life?

"Well, no," she replies. Then she stops, smiles, "Not that naughty, anyway."

But seriously, of Tyra, Palicki says, "She's not the usual bad girl. She's very smart. She could take the path of opening up her own business and becoming successful - or get a job at a strip club. She's like, really on the border of her life and what she could do."

Palicki not only feels she's met real-life Tyras - but that we all have.

"I think the great thing about our show is that people can relate to every character at some point - the quarterback, the cheerleader, the bad girl," she comments.

For Palicki, the prospect of becoming a known face to the masses is hard to fathom just now. She says, "I don't think you can ever be prepared for any form of publicity or fame coming at you for doing a show. I have my parents to keep me in check and keep my head on my shoulders so I'll do my best."

THE GIRL MOST LIKELY TO SUCCEED
America Ferrera of ABC's new "Ugly Betty" dramedy has already been hailed by such media outlets as the Philadelphia Inquirer as this TV season's breakout star -- "America the Beautiful," as New York Magazine put it, adding that she's the new season's "most unlikely swan." Her ABC series has wound up in numerous Top New Shows lists.

It couldn't be happening to a better young woman.

Ferrera, 22, is only too happy to become the torch-bearer for gals who are not likely candidates for cosmetics ads, but who have brightness, personality and determination to spare. In fact, she calls it "an honor."

"When I'm in character and I'm wearing Betty's costume, I never feel more confident, more beautiful, and more pretty on the inside," she told TV critics this summer.

Despite her unflinching, spit-hurling, glasses and braces-wearing awfulness as "Ugly Betty" in the new adaptation of the Colombian hit telenovela "Betty La Fea," 22-year-old America is actually a beautiful girl. She also has enormous talent. Those who've seen her film performances -- including her heart-rending "Sisterhood of the Traveling Pants" turn as the neglected daughter of a father who is marrying into a new family and her delicious portrayal of a girl from a poor immigrant clan who gets a full scholarship to Columbia University in "Real Women Have Curves" -- know she has it in her to be an acting powerhouse.

Raised by her Honduran immigrant mom in L.A.'s San Fernando Valley, America started acting at age eight in local theater and in school. Now, she's a student at USC, continuing her studies when not acting full-time -- double majoring in International Relations and Theater.

She says what's most important to her are the stories she can help tell as an actress. "Ugly Betty" (which boasts Salma Hayek as executive producer and cameo player) dares to place its frumpy protagonist in a high fashion magazine.

"To me, Betty is the most beautiful opportunity that's ever come across my path to represent a whole generation of young women who maybe don't recognize themselves in anything they're watching," said America. She's dealt with many casting directors, producers and other Hollywood types who couldn't see beyond the fact she is not stick thin - and lost out on a super talent as a result.

THE MAVERICK
In her role as the sardonically witty photographer, Kat, in CBS's new "The Class," Lizzy Caplan is going back to her roots, so to speak. She's forsaken the blonde locks she sported for the now-defunct "Related" series and returned to dark hair - the way she had it for her most enduring characterization, as nonconformist high school artist Janis Ian in the hit flick "Mean Girls."

"I got really used to being blond, trying to go against 'Mean Girls' in any way possible," admits the 24-year-old. However, "I do enjoy the way I look now," she says.

Caplan has had to contend with an artistically satisfying yet sometimes inconvenient situation in that she's so different in manner and appearance going role to role that she's gone unrecognized. When she goes out with close friend Daniel Franzese, who played her close friend in "Mean Girls," he's the one "who gets swarmed," she says.

She seems amused by that, making it clear that star trips and fame games aren't her style. Acting is. "I'd like to have a career that lasts more than a few years," she says. "It's been said before that the better you get at the red carpet, the worse of an actor you become."

She enjoys her "The Class" cast mates so far, she tells us. "Lucy Punch and Sean Maguire and I had met before, and Jason Ritter and I - we have some mutual friends and I had met him briefly before doing the show. He's the sweetest guy ever. Really wonderful. It's strange to meet people who are really kind, kind people especially growing up in Los Angeles and in this business. You expect them to have a hard edge, but he doesn't," she says of Ritter, whose father was the late John Ritter.

Caplan herself grew up in Los Angeles with family members who are involved in "the business," so she would know. She's been acting since high school, and has a sizeable list of credits - including "Freaks and Geeks," "Tru Calling" and "The Pits."

She admits the end of "Related" came as a bad surprise.

"At the beginning we were told how much the network loved it, that it would last forever. Then the merger happened," she says, referring to UPN and the WB melding into the new CW network, "and that changed our fate. There's no security in any job, I'm figuring out.

"A lot of my friends had been going out for 'The Class,' but I wasn't too hot on doing a half-hour comedy," she continues, dead pan. "I was used to the kind of schedule where you work every day and have no life for months and months. That was the life I was used to and that was what I wanted."

Nevertheless she couldn't help but be attracted to "The Class" and its pedigree - the creators being David Crane ("Friends") and Jeffrey Klarik ("Half & Half," "Mad About You"). The show about a group of one-time third grade classmates who reunite 20 years later garnered good pre-season notices.

"I was sad about 'Related,' but this show feels really right," Lizzy says. And besides, she's tressed for success.