Joanne Froggatt has made a surprising revelation about her "embarrassing" encounter with the Duchess of Cambridge back in 2015.MORE: Downton Abbey's Joanne Froggatt makes extremely candid comment about her divorceThe 41-year-old actress, who plays Anna Bates in the beloved period drama, reflected on the royal's visit to the Downton Abbey set and revealed how Kate appeared slightly taken back by a quip she made.WATCH: Downton Abbey releases official trailer for sequelDuring rehearsals, Kate