Allison Williams goes topless for Harper's Bazaar

NEW YORK, Nov. 3 (UPI) -- Allison Williams recently went topless for Harper by Harper's Bazaar magazine.

The 27-year-old actress stripped down for the publication's December/January issue, which she also guest edited. Williams shared photos from the spread and discussed self image Monday on Instagram.

"I am particularly proud of this one," she captioned one ab-flaunting picture. "For my whole life until 2 years ago, I was super self-conscious about my stomach. I dreaded bikini season. I kept it covered. Boyfriends weren't allowed to touch it. No amount of crunches seemed to strengthen it."

"Then I met @ilariacavagna who introduced me to the magic and focus of Pilates," she shared. "I have never felt stronger, healthier, more focused, or more feminine. Now, I love my stomach because it keeps me grounded to my core. And it's still the same stomach! Here's to proving yourself wrong."

Williams previously told Town & Country magazine she is "by far, [her] own worst critic," but expressed relief over "finally abandon[ing] the pursuit of perfection." The actress lost a significant amount of weight in the past two years, and discussed scrutiny about her figure with Allure last year.

"[It was my] college weight," she explained. "But that's still the way it was set in people's minds, so they're like, 'Oh my God, you've lost weight.' And I'm like, 'This is just the way my body is very naturally.' It's a bit stressful to know that there are a lot of people walking around who think I'm constantly just shaking and depriving myself."

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Allison Williams for the December/January issue of Harper by Harper's Bazaar magazine. Instagram/Harper's Bazaar

Williams is best known for playing Marnie Michaels on HBO series Girls, which will return for a fifth season Feb. 21, 2016. She is the elder child of former NBC Nightly News anchor Brian Williams, and married College Humor co-founder Ricky Van Veen in September.