Sports Illustrated recently released behind-the-scenes footage of Kate Upton's photo shoot in Antarctica for the magazine's annual swimsuit issue.

The footage, posted July 5 on YouTube, shows exactly how the 21-year-old Florida native braved the freezing temperatures while wearing only a two-piece for her 2013 magazine spread and cover.

The footage includes clips of members of the production team playing in the snow while being surrounded by penguins. Upton walked around the glaciers with white furry snow boots and nothing else but a white bikini. Penguins made times came on the set where the photographer was shooting and stood at one point in the background of Upton's shot. 

Avoiding the topic of how cold she really is, Upton merely says toward the end of the clip "I'm good at pretending I'm warm." She also keeps things playful by throwing a snowball at the cameraman and lying on snowy ground. The photo crew goes for a swim and a penguin named Hopper takes over as tour guide as the video ends.

Upton's 2013 S.I. cover photo shoot in Antarctica was done in December 2013. The Swimsuit issue came out in February.

This year marks the second consecutive year that Upton was the cover girl for S.I.'s famous swimsuit issue. She joined past cover girls such as Christie Brinkley, who graced the front three years in a row from 1979-1981. Elle Macpherson did the same between 1986 and 1988; Paulina Porizkova posed in 1984 and 1985 and Tyra Banks starred in 1996, along with Valeria Mazza) and 1997. 

Tags: Kate Upton