Kristen Stewart Blames 'Marie Claire' for Her 'Resting B**ch Face'

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"They told me to do that!"

Kristen Stewart has an explanation for all those surly magazine covers.

The 25-year-old American Ultra actress appeared on The Tonight Show Starring Jimmy Fallon on Tuesday, where she once again insisted that despite her super-serious reputation, she actually does know how to smile. When Fallon held up her recent Marie Claire cover as an example of her intimidating facial expressions, Stewart explained that it's not always her choice.

Marie Claire

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"They told me to do that!" she exclaimed about the fierce photo. "That's like a model-y ... that's what a magazine thing does. That's magazine stuff, right? … I blame Marie Claire. Marie Claire ruined my reputation," she joked.

But there was no hiding Stewart's signature sass, when she explained her response to journalists who asks why she's not smile-y. "I can do it [smile], -- whether or not I smile at you," she deadpanned.

Still, she was game enough to play a game of "Word Blurt" with Fallon -- in which the two both say the first word that comes to mind based on a random word -- when all her awkward glory was put on display.

"I'm not very good at the whole improv, joke thing," she rambled.

Though we have to say, her obvious struggle is charming none-the-less!

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In her Marie Claire interview last month, the former Twilight star refused to apologize for her public persona. "Lately, I've been doing less of the 'I'm sooooo sorry.' And more of the 'No. F**k. Jesus,'" she said bluntly. Watch below: