Jul 28, 2015 @ 12:00 pm

Welcome to I'm Obsessed, a daily video series with Kahlana Barfield, InStyle's fashion and beauty editor at large. Check back every weekday to learn more about the beauty products and tools she can't get enough of.

Jessica Simpson once sang about how beautiful she felt with “nothing but a T-shirt on,” and well, we couldn’t agree more. American’s favorite wardrobe staple pairs well with just about anything (think jeans, culottes, pants, skits, shorts, blazers, and more) and can also be worn to both casual and sophisticated outings. And while we all have a go-to neatly folded in our closet, ATM’s Sweetheart Tee is an absolutely must-have thanks to its curved neckline, soft shoulder pleating, and fresh, insanely comfortable cotton finish. Say hello to a fresh take on your already-perfected summer uniform.

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Shop it: black, heather grey, white, $76;

Watch the video above to learn why Barfield loves them—and visit tomorrow to see what else she's in love with.