>>6 I thought that too. At Golden Globes it really didn't look like she had an ample chest. Then I googled Brie Larson 2016 to make sure and it looks like she's always had the same size but just didn't wear outfits that emphasized them:

http://celebmafia.com/wp-content/uploads/2016/01/brie-larson-2016-palm-springs-international-film-festival-awards-gala-1.jpg

http://www.hollywoodreporter.com/sites/default/files/custom/Stephanie/Sam/Brie.jpg

Then at Comic Con 2016 she dresses similar to SI promo: http://tomandlorenzo.com/wp-content/uploads/2016/07/Brie-Larson-Marvel-Panel-San-Diego-Comic-Con-2016-Red-Carpet-Fashion-Gabriela-Hearst-Tom-Lorenzo-Site-3.jpg

I'm guessing award season dressing is much more demure than shilling action adventure promo lol gotta bring in those fanboys!