Reese Witherspoon speaks out on arrest: 'I made a mistake.'

Reese Witherspoon is speaking out about the impact of her 2013 arrest on her previously squeaky-clean image.

"I think it was a moment where people realized that I wasn't exactly what they thought I was," the Oscar-winning actress told reporters at the press conference in London for the U.K. premiere of her new film Wild. "I guess maybe we all like to define people by the way the media represents them, and I think that I showed I have a complexity that people didn't know about.

Reese and husband Jim Toth were arrested in Atlanta on April 19, 2013 for driving under the influence (him) and disorderly conduct (her). She apologized about the incident at the time in a statement, but has clearly reflected on the events since then.

"It's part of human nature. I made a mistake. We all make mistakes," the 38-year-old told reporters Monday. "The best you can do is say sorry and learn from it and move on."

Click on the photo for more pictures from the event.

The actress attended the premiere at the 2014 BFI London Film Festival in a dramatic black and lace cut-out gown, with smoky eyes and red lips.

Wild is based on Cheryl Strayed's memoir, which was a New York Times bestseller. It tells the true story of the author's transformative 1,110-milks hike along the Pacific Crest trail in the wake of a harrowing personal tragedy. This cinematic adaptation is already being considered a strong award nominee, and could find Reese earning a second Oscar nomination in the wake of her win for 2006's Walk the Line.

Reese discussed some of the film's key scenes at Monday's press conference, saying her character's inexperience was simple to capture.

"When you see me putting together the tent, that's literally me putting together the tent. It took me two hours," she admitted.

To reinforce the realism, director Jean-Marc Vallee pulled out all the stops. Reese revealed that she'd been hoping that her character's rucksack would be filled with newspaper, but the director insisted that it be a genuinely heavy load to mirror Strayed's burden. "I got there on the day, and Jean-Marc said, 'Actually, I think it would be better.' And I said: 'Are you joking?' And he said, 'No, I think it would be better' and then just walked off."

She continued: "So I ended up carrying it the whole time. I've never been as strong as I was after that movie. I had a back problem."

Wild opens in the U.S. on December 5, 2014.