In a tweet by Collider reporter, Steven Weintraub, Captain America himself has confirmed when the sequel will start filming.
Look for more news about Cap's next big adventure to start heating up soon-ish, since casting for movies usually start ramping up several months before its production begins.
More stories on Captain America:
Captain America: The Winter Soldier to Have 'Darker, Edgier Sensibility' to the Story
Captain America The Winter Soldier News: Bucky Barnes is Back and Sebastian Stan to Reprise Role
Captain America News and Opinion: Falcon Confirmed as Cap's New Sidekick But Who is Winter Soldier? - SPOILERS