"Very interesting ..."
Arte Johnson (January 20, 1929 – July 3, 2019).
Arthur Stanton Eric Johnson was an American comic actor who was best known for his work as a regular on television's Rowan & Martin's Laugh-In from 1968 to 1973, on which he played many characters, including "Wolfgang," a cigarette-smoking German soldier oblivious to the fact that World War II was long over, as he skulked while hidden behind a potted plant. He would then invariably comment on a preceding gag with the catchphrase "Very interesting ..."
He appears as Crandall in Is There a Small Hotel (Season 8, Episode 23) of The Donna Reed Show.