UPDATE: 1/10/11 12 PM PST Turns out, this is a fan manipulated photo utilizing a photoshopped image from Across the Universe. Good eye, commenters.
All I had to say was: Nude! Yes, Kristen Stewart and Robert Pattinson were photographed shooting an underwater kiss for their upcoming Brazilian honeymoon scenes in The Twilight Saga: Breaking Dawn - Part 1. There was a question as to the photograph's authenticity, but it has been disappearing quickly across the net. So take a look before it's gone. It may not be around for very much longer:
The Twilight Saga: Breaking Dawn - Part 1 was released November 18th, 2011 and stars Robert Pattinson, Kristen Stewart, Taylor Lautner, Ashley Greene, Billy Burke, Anna Kendrick, Nikki Reed, Jackson Rathbone. The film is directed by Bill Condon.