After the Twilight star was caught cheating, she didn't deny or stall—she just said, "I'm so sorry."

It took nearly three months for Tiger Woods to apologize after his multiple extra-marital affairs became public. Anthony Weiner waited a week after he unintentionally posted a lewd photo of himself on Twitter to say sorry for his R-rated use of social media. Singer-turned-actress LeAnn Rimes cheated on her husband with a co-star—and didn't publicly apologize until a year and a half later, after she'd been divorced and re-married.

Kristen Stewart waited less than a day. Late yesterday, Us Weekly published photos of "steamy rendez-vous" between her and her Snow White and the Huntsman director Rupert Sanders. By Hollywood standards, the affair is a big deal: Sanders is married with children and is twice Stewart's age—plus his wife Liberty Ross played Stewart's mother in the Snow White movie. Even more remarkable is the fact that Stewart for years has been dating Robert Pattinson, her co-star in the ridiculously popular Twilight series. As Vulture put it, "That sound you hear is a thousand Twilight: Breaking Dawn 2 publicists simultaneously breathing into a paper bag. Press tour should be ... interesting."

So it would have been completely normal for Stewart to stall the way Woods and Weiner and Rimes (and Meg Ryan and Mark Sanford and Ashton Kutcher and Bill Clinton) did when their infidelities came to light. She could have refused to speak to the press or said that the damning photos were a joke. But she didn't. By midday today, she issued the following apology:

I'm deeply sorry for the hurt and embarrassment I've caused to those close to me and everyone this has affected. This momentary indiscretion has jeopardized the most important thing in my life, the person I love and respect the most, Rob. I love him, I love him, I'm so sorry.

The apology is remarkable for a bunch of reasons: It seems heartfelt ("I love him, I love him, I'm so sorry" oozes far more contrition than Woods's stilted, rambling 2010 statement); it's revealing (Stewart had never officially acknowledged her relationship with Pattinson before); but most of all, it was fast. Has any high-profile cheater ever said sorry so quickly?

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Lots of factors could account for the apology's rawness and swiftness. A cynic would point out that Stewart has tremendous financial incentive to make this scandal go away as soon as possible. The last installment in the Twilight saga is scheduled to come out in November, and as Meg Ryan knows, a movie with an adulterous actress has a good chance of bombing. Perhaps in acknowledging and apologizing for the affair now, Stewart's hoping that her teenybopper audience will have the opportunity to mourn, rage, and then forget about the whole thing by the fall.

But Stewart has never much cared what her audience thinks of her. She once said being a celebrity is like being raped—and in her subsequent apology shrugged, "I've made stupid remarks before, and I've always reasoned: 'Whatever. They can think what they want.'" She refuses to smile for the camera on the red carpet, and when she poses for magazine covers she often looks like she's got a gun pointed at her head. Unlike her peers Taylor Swift and Selena Gomez, she doesn't market herself as a role model. It's hard to imagine that she's had a change of heart and suddenly wants people to like her or to think of her as a paragon of chastity.

In fact, Stewart's blase attitude toward her own image could explain why she apologized so quickly and with so much apparent emotion. She didn't try to see if she could trick the public into believing the affair didn't happen. She didn't wait for a damage-control expert's opinion on what sort of statement would sound best to her fans. She just wanted forgiveness, so she asked for it.