WITH AN EYE ON . . . : If you’re ‘Mad’ about her new ‘Friends,’ you’ve gotta love Lisa Kudro

Lisa Kudro’s glad she’s got “Friends.”

And she’s very thankful NBC has told her they’re still “Mad About You.”

Starting this week, viewers get a double dose of Kudro, who’s in both NBC shows this season.

Kudro, who plays hippy-dippy Phoebe on the new ensemble show, will continue to play ditzy waitress Ursula on the network’s hit “Mad About You.”

“I was hoping to continue on ‘Mad’ and be on ‘Friends,’ ” she says from her West Hollywood apartment. “It’s great it worked out this way!”

The 31-year-old Tarzana native may play airheaded blondes on both shows, but she’s an Ivy League grad with a degree in biology who had every intention of going to medical school and follow in her father’s footsteps. Her dad’s a world-renowned headache specialist.

Secretly, though, Kudro was always interested in comedy--she performed through junior high. But by high school, she then “took school very seriously” and became devoted to studying. Was she a brain at local Taft High? She responds modestly: “I guess I was . . . a couple of people called me ‘Einstein.’ ”

Einstein? Certainly there couldn’t be a nickname more incongruous for Phoebe or Ursula.

Kudro laughs and says there might be a little bit of Phoebe and Ursula lurking in her: “Sometimes when I’m really concentrating on something, I tune out everything else and that makes me seem airy, I guess. I studied all the time in high school and wanted to get into a good school. That was very important, so by the time I got to Vassar, I was happy and smiling all the time, so a lot of people thought I was stupid.”

While at Vassar she was determined to become a researcher. She explains in a very un-Phoebe or un-Ursula way: “I’ve always been interested in evolutionary biology, specifically, I’m interested in looking at the evolutionary behavior, how it’s biochemically translated. It’s neuropsychological pharmacology.”

Despite this interest in heady things, she was finally sidetracked by encouragement from her older brother’s best friend: comedian Jon Lovitz.

“I’ve known him since I was 3,” she says. “And when I confessed I was interested in comedy, he suggested I go for it.”

She became a member of the comedy troupe The Groundlings, which led to a recurring role on “Bob” and other television guest spots.

She may have caught the public’s eye with her quirky role in “Mad About You,” but “Friends” executive producers and creators Marta Kauffman and David Crane (“Dream On”) didn’t recognize Kudro during her audition.

“I honestly didn’t connect the name with the face,” Kauffman says in a phone call from the “Friends’ ” set. “Most actresses could ‘get’ Phoebe, but Lisa made her a real person, and made her funnier. She brings us wonderful jokes and ideas.”

Phoebe, Kauffman points out, addresses all of the “New Age” folks preoccupied with spirituality. But the character isn’t without her pathos. “She brings the show humor from an odd place,” the producer says. “The character has such a dark and strange background and continues to have a positive view of the world and just wants to help everyone. Lisa just embodies all that in the show.”

Despite all this good will and good luck, Kudro wishes she could feel just a bit more confident. “I have a weird superstitious side,” she confides. “All these good things are happening, and it makes me think that something bad might happen. That probably sounds really annoying! But I really love both shows!”

She does however, feel confident enough to pursue even more. There may be a one-woman show in the works. And, like most newly popular actors, this windfall has brought her enough financial reward to consider a new house and maybe a new car.

Those dreams may become reality if her new show takes off: “Friends” has the enviable “hammock” slot between “Mad” and “Seinfeld.”

“Mad About You” and “Friends” air Thursdays on NBC at 8 p.m. and 8:30 p.m. , respectively.