It's difficult to tell who we're seeing in the shadowy and somewhat blurry photo -- click to enlarge! -- but it's most likely star Daniel Craig, whose character Zeke Jackson has "a mysterious shackle" on one wrist.
The DreamWorks/Universal film, about cowboys, Apache warriors, outlaws and simple townsfolk who unite to fight aliens in 1870s Arizona Territory, also stars Harrison Ford, Sam Rockwell, Olivia Wilde, Paul Dano, Keith Carradine and Clancy Brown. You can read the synopsis here.
Cowboys & Aliens is set to premiere on July 29, 2011.