I know that these pics are a few years old, but honestly if I didn't know when they were taken, I'd think it was quite recently. The reason that I'm searched out all these pictures is that I was going through my closet yesterday, and I stumbled upon the exact shirt she's wearing, albeit in navy and not gray. It's one of those things I really loved when I bought it and have since kinda forgotten about, but these pics have made me want to drag it out again (I'm wearing it right now!).
It's this American Apparel Tri-Blend Light Weight Raglan Pullover, $36 at americanapparelstore.com:
I really love the way Mary Kate styled it. The bagginess, offset by the pushed-up sleeves and wide scoop neckline, is so casually chic. It might not seem that flattering, but it is, I promise. All the exposed skin negates the frumpiness of the boyish shape, and you can wear it off one-shoulder for an even girlier look. Plus, it hits at a great place on the hip, right below any lovehandle business (guilty), but above the top of the leg. It's super versatile, as seen on Mary Kate. I'd wear it balanced by a pair of straight-leg jeans, maybe with a brown leather belt like in pic 1, with a big, drapey scarf, tons of jewelry, and a relaxed hobo bag. And it's so affordable, you can buy it in multiple colors! I'm def putting the grey version on my wishlist (it also comes in non-melange colors, if that's your thing).
Mary Kate in order: whowhatweardaily.com, fashionchalet.blogspot.com, stardustandsequins.wordpress.com, American Apparel top: americanapparelstore.com