Birkenstocks are already known to be a cushiony sandal, but add a platform and you're set to wear them all day at a festival!

14 Sleek, Wide-Leg Boots You Can Buy for Under $200 1. Buttery-Soft: There are tons of wide-leg sizes available in these leather knee-high boots. Shoppers confirm they fit muscular calves comfortably.

But while fans speculate if the singer will attend the event in Austin this Sunday, some of her collaborators on the "Cowboy ... boots with a brown suede upper and a short block heel.