Doctor in the House is the 20th episode of Season 6 of Three's Company, and the 120th overall episode of the series. Written by John Boni and directed by Dave Powers, it first aired 2 March 1982 on ABC.
Summary[]
Having once told his grandfather that he is a doctor, Jack is now in a panic because the elder Mr. Tripper is coming for a visit. Rather than take Janet's advice of immediately revealing the truth, Jack continues with the charade and finds himself in a bind when Grandpa insists on visiting his office at the hospital. Terri gives in to Jack's begging and lets Jack borrow the office of a doctor who is away, and Janet agrees to act as Jack's "patient." The mix-ups continue when an intern arrives to observe the "doctor," and when Mr. Furley comes in to see the real doctor about his bad back. Jack is finally forced into a full confession and is forgiven by his loving grandfather.