The 25-year-old shared a snap of herself not wearing a scrap of slap, with the hashtag #iwokeuplikethis.
The thing is, she probably actually did - not that we're jealous or anything. Have you ever seen skin this perfect, eyebrows just so well-shaped? Yep, Smalls is a natural beauty, make no mistake.
And, rather generously, the Puerto Rican star shared her beauty must-haves with US Elle last year. When it comes to getting skin this glowing, she said: "I always carry Estée Lauder products, especially now for the sun. Something that has SPF 15 is really important for your skin, and making sure [your skin is] well moisturised."
As for makeup, Smalls said she loves turquoise eyeliner and has experimented with purple mascara.
Speaking to The Guardian, head of the social media for the charity Aaron Eccles said: "We're over the moon. When we do a social media campaign we want to engage as many people as possible, and this has taken off like crazy."
The last star to post a no makeup selfie on Instagram was US singer Demi Lovato and the first was Cameron Diaz.
Want to find out more about the charity campaign? Catch up with the video below...