While the race to join the 'Guardians of the Galaxy' cast heats up, with Joseph Gordon-Levitt dropping out to pursue greener pastures in 'Sin City: A Dame to Kill For,' Marvel is getting things ready for when those announcements finally happen.

Word has come from the folks over at Screen Daily about the production start date for Marvel's upcoming 'Guardians of the Galaxy,' which is reported to start in March following the wrap of 'Captain America: The Winter Soldier.' The studio is taking the project to London, where sections of 'Thor: The Dark World' were filmed.

Hopefully this means the 'Guardians of the Galaxy' cast will be finalized by then. With Joseph Gordon-Levitt out of the picture, the latest reports put Zachary Levi and Jim Sturgess as top picks for the leader of the superhero team, Star-Lord (aka Peter Quill). Not much has been revealed in terms of the other members, but Dave Bautista ('The Man With the Iron Fists'), Isaiah Mustafa (the Old Spice guy) and Brian Patrick Wade ('The Guardian')  are reportedly in the pool for Drax the Destroyer.

The film isn't even scheduled to hit theaters until May 2015, so there's still plenty of waiting to be had. Keep tabs with us, though, for all the latest 'Guardians of the Galaxy' casting.