Wilhelmina Slater may be the only Ugly Betty character on EW’s list of TV’s Best Bitches (do check it out in the issue on newsstands right now), but for Vanessa Williams, who’s scored an Emmy nomination in each of the show’s first three seasons, bringing the ferocious editrix to life is hardly a solo effort. “The comedy comes from what’s on the page for sure,” she says. “Our writers are brilliant. I never know what’s going to come out of my mouth. And the people I get to play with are amazing!”

Williams says she especially enjoys when Willy is bantering with loyal sidekick Marc (Michael Urie) or baring her claws at rival Claire (Judith Light). “This season we’ve had some great stuff with Wilhelmina and Claire going back and forth, which is always tasty, because it’s two women of a certain age. Willy is basically calling Claire a corpse on a daily basis, and Claire retorts with ‘You scheming, conniving bitch,’ which is the reality,” Williams says with a hearty chuckle. And although the show’s writers have allowed us to see the softer side of Wilhelmina — through her failed romances, her rocky relationship with her father, her struggles to connect with her daughter — the woman never loses her beastly edge. “We’re about to shoot a scene, I think it’s for episode 11, and I’m tempting Becki Newton’s character with all this couture, luring her like the evil queen in Snow White,” says Williams. “I say to her, ‘Amanda, Amanda…it is Amanda right?’ After four years, she still doesn’t realize it’s her name!”

Of course, four seasons into Ugly Betty‘s run, Wilhelmina often doesn’t need to say a single word to strike terror into the hearts of her underlings. “A lot of the stance, the carriage, and the facial expressions are where the real power lies. That’s what makes Wilhelmina great,” says Williams.”Sometimes  it’s just a look or a sigh or a roll of the eyes or a turn of the back, and that’s weighted enough. It’s been my favorite role of a lifetime, and I truly enjoy coming to work every day.”

Check out bonus footage below of Williams during her photo shoot with Glee‘s Jane Lynch and The Good Wife‘s Christine Baranski to learn about the actress’s favorite Ugly Betty zinger, the reaction shot she most enjoys delivering, and the secret to surviving in Wilhelmina’s super-pointy, spike-heeled shoes. And for more on Ugly Betty and TV’s best bitches, check out Michael Ausiello’s latest Betty scoopfest, Tanner Stransky’s weekly rundown of the show’s best dialog, and bonus quotes from Mandi Bierly’s interview with The Vampire Diaries‘ Ian Somerhalder. (Yep, we’ve placed his deliciously evil Damon Salvatore right alongside Wilhelmina in the TV Bitch Hall of Fame.)