After bringing the main cast of Guardians of the Galaxy to Comic-Con this past weekend, it has been announced that filming has officially started. Along with the announcement, we have confirmation of the full cast and the characters they will be playing. Take a look at the concept art below to get an idea of what the main heroes will look like in the movie.

We were at the Marvel press conference, which included most of the Guardians of the Galaxy cast, and we've included some photos below. Doctor Who fans who didn't catch the Hall H panel should be surprised to see that Karen Gillan shaved her head for the role of Nebula.

"BURBANK, CALIF. (July 23, 2013) – “Guardians of the Galaxy,” the next epic adventure from Marvel Studios has started shooting at the UK’s Shepperton Studios. Directed by James Gunn (“Slither,”“Super”) from his screenplay, with a story by Nicole Perlman and Gunn, the film will introduce audiences to a whole new side of the Marvel Cinematic Universe. The all-star cast includes Chris Pratt (“Zero Dark Thirty”, “Moneyball”) as Peter Quill aka Star-Lord, Zoe Saldana (“Star Trek Into Darkness”, “Avatar”) as Gamora, Dave Bautista (“Riddick”) as Drax the Destroyer, Lee Pace (“The Hobbit,” “Lincoln”) as Ronan the Accuser, Michael Rooker (AMC’s “The Walking Dead”) as Yondu, Karen Gillan (BBC TV’s “Doctor Who”) as Nebula, two-time Academy Award® nominee Djimon Hounsou (“Amistad”, “Gladiator”) as Korath, with Academy Award® winner Benicio del Toro (“Traffic”) as The Collector, Academy Award® nominee John C. Reilly (“Chicago”) as Rhomann Dey, and six-time Academy Award® nominee Glenn Close (“Albert Nobbs,” “Fatal Attraction”) as Nova Prime. Marvel’s “Guardians of the Galaxy” is slated for an August 1, 2014 release in the U.S.

Marvel Studios’ President Kevin Feige is producing the film. The executive producers are Louis D’Esposito, Victoria Alonso, Jeremy Latcham, Alan Fine and Stan Lee; the co-producer is Nik Korda.

The creative team includes director of photography Ben Davis, BSC (“Wrath of the Titans”, “Kick-Ass”), production designer Charles Wood (“Thor: The Dark World”), BAFTA-nominated Editor Fred Raskin (“Django Unchained,” “Fast Five”) and Academy Award®-winning editor Hughes Winborne, A.C.E. (“The Help,” “Crash”), and Academy Award® winning costume designer Alexandra Byrne (“Marvel’s The Avengers,” “Elizabeth The Golden Age”). The film will also shoot at Longcross Studios, and locations in and around London."

The concept art is courtesy of the official Guardians of the Galaxy Facebook page.