HOLLYWOOD - Like the delicious troublemaking assistants they play on

Ugly Betty

, Michael Urie and Becki Newton complete each other's sentences, enhance each other's jokes, and are crazy about each other. (So much so that Urie has moved to the apartment building where Newton and her husband, actor Chris Diamantopoulos, live.)

They met last year in New York, two struggling actors looking for their big break. Urie, 27, a Juilliard graduate, had spent his career in theater. Newton, 29, had guest-starred on a few TV shows, including Charmed, American Dreams, and Law & Order: SVU.

Coincidentally, they had approached their Ugly Betty auditions with the same kind of self-protecting abandon that is a byproduct of the acting rejection mill.

Newton pictured Amanda Tanen as a leggy, skinny model much taller than she is. She figured she never would land this character part, especially after blowing two other pilot auditions that same day.

For audition No. 3, the scene was the moment that Betty (America Ferrera) arrives at Mode magazine sporting a Guadalajara poncho and Amanda snipes: "Are you the before?"

"I was bored. I was angry. I was hungry," Newton said as she curled up on a poolside couch at the Roosevelt Hotel in Hollywood, covering the tiny piece of fabric posing as her dress (Amanda's wardrobe) with a hotel bathrobe. "All of the things that Amanda is all of the time. So I said it with lots of anger and bitterness behind it."

Although Urie believed he could handily portray the "bitchy gay assistant" Marc St. James was supposed to be, the role was only for the pilot, so he had no hope for a steady gig.

But then it occurred to him to grab one of the casting executives and pretend he was injecting Botox into her face, just as the script called for Marc to do to his boss, Wilhelmina Slater (Vanessa Williams).

"We were trying to find a girl that is gorgeous and funny, and that's a lot tougher than you think," creator Silvio Horta said. "It's really rare. And Becki came in and she was beautiful and she just nailed it. We were howling in the room. With Michael, he was doing a play, playing a geologist, and he came in with this beard and looking completely unlike Marc. But he was just so funny and his timing was so perfect that, even though his part was initially conceived as a guest star, when we saw the dailies, we were like, 'Oh, this guy is just fantastic.' "

Fans shudder to think of an Ugly Betty world without this catty couple and their over-the-top shenanigans. What other attention-starved characters on TV would go for disrobing on a red carpet to get the attention of the paparazzi, as Amanda, provoked by Marc, did this season?

Moments like this have catapulted Marc and Amanda to much-watched coupledom, even though he's gay and she, to put it nicely, has issues with monogamy.

"I think what's fun about watching them is that Betty is the heart of the show, and she's the character we identify with," says Horta. "But they're the little devil on our shoulder. They say the things that everyone thinks."