LOS ANGELES, Calif. --
The third installment of “The Twilight Saga” premieres on Wednesday, but already Robert Pattinson and Kristen Stewart are two of the world’s most powerful celebrities, according to Forbes Magazine.

The on-screen couple, who are rumored to be a pair off-screen as well, debut on the coveted list for the first time, with Robert taking spot #50 and Kristen trailing at #66.

Oprah Winfrey, who was trumped by Angelina Jolie last year, reclaimed her #1 spot on the annual Forbes list with earnings of $315 million.

Other newcomers to the list included Lady Gaga who appeared in the #4 spot with earnings of $62 million, as well as James Cameron who thanks to “Avatar” earned #3 spot with $210 million in earnings.

Additional first time appearances included Conan O’Brien (#51), the Black Eyed Peas (#16), Robert Downey, Jr. (#73), and Chelsea Handler (#98).

Sandra Bullock, who had a rough year in her personal life, scored high on the list professionally, earning the #8 spot with $56 million in earnings.

What happens when you promote not one, but two films – on back-to-back red carpets?

For Kristen Stewart, the result is a severe case of the high-heel blues.

"I feel like my feet are really pissed off at me, just because of the shoes," Stewart told PEOPLE at the premiere of her new indie drama Welcome to the Rileys on Friday. "That’s been the biggest problem."

One night earlier, the actress, 20, strutted the carpet at the L.A. premiere of the new Twilight film, Eclipse, which she has been promoting around the world. But she says she’s not exhausted by the publicity grind – much the opposite, in fact.

"By the end of the day I actually get really hyper, because it's then that I have my own time," she says. "You end up staying up all night and then screwing your morning the next day because you need time to yourself."

As for her intensely emotional role in Rileys, in which she plays a teenage prostitute, "the subject matter was a lot sadder and emotionally distraught than I've ever had to deal with," says Stewart. "It's sort of the lowest of the low that I've ever had to go."

Is she worried about how Twi-Hards will respond to seeing her in such a different role?

"Luckily Bella wasn't my first part," she says. "I've had the chance to really get comfortable with keeping true to why I do what I do, and I can only do it this way. I'm proud of myself – so if other people aren't, that's totally cool."