We take an educated guess at his mystery role.

Captain America: Civil War is shooting right now, and Marvel has just announced another addition to what is, honestly, an already enormous cast: Martin Freeman. Freeman, who was wonderful in The Office and perfect in the deeply flawed Hitchhiker's Guide to the Galaxy and profoundly underused in The Hobbit movies, has come aboard in a mystery role. The release did not reveal his character. Someone on Twitter suggested he could be Henry Peter Gyrich, who was The Avengers' government liaison in the comics, but Fox seems to have that character (he showed up in X-Men). 

I do suspect that he is playing some sort of government type, though. Sources have told me to expect Freeman to also show up in Black Panther. Does that mean he's a character from that comic? Is he Everett K Ross, the American envoy to Wakanda from the pages of Ka-Zar? It would be easy to make that character a UN rep and allow Freeman to have his standard accent. That would actually make a whole lot of sense, the more I think about it - but I'm just spit-balling here. 

I'm incredibly excited about Civil War, especially after Age of Ultron really redefined the relationship of Steve Rogers and Tony Stark - they ended the film pals, but that wood chopping conversation still lingers. I can't wait to see it explode.