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When it came time for Shailene Woodley's impromptu close up, the 25-year-old actress wished she thought it through.

The "Big Little Lies" star opened up about getting arrested and her widely publicized mugshot to Stephen Colbert on "The Late Show" on Monday.

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"I wish I'd known that this was going to be as public as it was. I would have made, like, a face," she admitted. "I'm just looking at the person, like, 'Are you kidding me right now?'"

Woodley was arrested back in October while protesting the Standing Rock Pipeline. The arrest was filmed on Facebook Live, thanks to Woodley's mom.

"I handed her my phone and I was like, 'Keep recording,'" she recalled. "I can't imagine, actually, what it would be like to watch your daughter handcuffed and taken away."

The outspoken activist still thinks it's important to lend her voice to the causes close to her heart.

"The front lines don't necessarily have to be in North Dakota," she said. "The front lines can be wherever you are. You can create a protest in New York City, because protests are about awareness and about people coming together. I think one of the biggest ways that we're going to defeat this pipeline more so than even protesting on the frontlines is to divest from these big banks that are invested in the pipeline."

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She added that she would be starting the site http://howtodivest.org soon to help members of the public keep their money from banks and companies supporting issues that conflict with their beliefs.