Colman isn't the only new cast member for season three. Since season three takes place in the late '60s and into the late 1970s, the series is replacing the main cast with new, older actors to more accurately portray the passing of time. Helena Bonham Carter has signed on to play Princess Margaret and Ben Daniels is on board as as Antony Armstrong-Jones.
In addition to those casting updates, Tobias Menzies will play Prince Philip and, eventually, season four will introduce Princess Diana. See the first glamorous images from the upcoming season ahead.