It's National Smoothie Day, which means it's time for a sweet treat ... like this gallery of sexy celebs sippin' on their favorite fruity beverages!!!

Stars like Heidi Klum, Winnie Harlow and Sabrina Carpenter clearly love their Erewhon smoothies, so they'll probably be celebrating today ... and taking time out to get their smoothie fix.

But they aren't the only ones ... grab a smoothie and check out our gallery of all these celebs sipping something sweet!!!

Trust us, there's a lot of fun, fruity photos to enjoy here ... and you just might see your favorite star.