That reminds me of the Columbo where he meets the woman who played the housekeeper (or something) in Macmillan And Wife playing 'herself - actress from Macmillan And Wife' (if I remember correctly) And of course Macmillan and Columbo were both in the 'Mystery Movie' series.
And hey, also in "Uneasy Lies The Crown", Columbo recognized Dick Sargent who played the second Darrin Stephens on "Bewitched". So then how come he didn't recognize David White (who played Larry Tate on "Bewitched") when HE was in the "Identity Crisis" episode playing the head of the CIA? (Or the woman who played the second Gladys Cravitz on "Bewitched" when she was in "Suitable For Framing" as an art gallery attendee???) Or Agnes Moorehead when she played the part of the wife murdered in the original play version of "Prescription: Murder" when Columbo wasn't even being played by Peter Falk?!