Editor MJ Day has posted a rear shot of the magazine's mystery model wearing nothing but a painted-on swimsuit on Instagram.com, but a tattoo on her wrist suggests it's mixed martial arts fighter-turned-actress Rousey.

The new issue, featuring some of the world's most beautiful models posing for shoots in exotic locations, will hit shelves in February (16).

Meanwhile, Rousey has a busy year ahead of her - as well as preparing for the rematch of a fight she lost to Australian Holly Holm last year (15), the action woman is also set to start work on the Road House remake, in which she'll take on the character portrayed by Patrick Swayze in the original.