"It was everyday wear," Upton says. "I dont really see what's wrong with being in a swim suit."
Despite her comfort in a bikini, the 2013 SI cover girl wasn't exactly in her element when faced with the sexy shoot in frigid Antarctica.
"There was no way for me to prepare for Antarctica weather," laughs Upton. "It was summer and 20 degrees with a high of 20. The sun was out most of the days and it was beautiful, but I'm from Florida."