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Before Battlestar, John Colicos was well known in the science fiction community in his role as Commander Kor, the first Klingon seen in the original Star Trek. He reprised the character of Kor for the third Star Trek series, Star Trek: Deep Space Nine in three episodes: "Blood Oath", "The Sword of Kahless", and "Once More Unto the Breach".
Colicos was a Canadian and a well-received Shakespearian actor. He is also well known as Dr. Mikkos Cassadine from the TV soap opera, General Hospital.
Colicos' final acting appearance was his reprise of Baltar in the mock trailer Battlestar Galactica: The Second Coming, aired at many science fiction conventions in 1999.
Colicos was married to Mona McHenry from 1956 to 1981, when they divorced. They have two children, one of them actor Nicholas Colicos.
Describing his acting philosophy: "When all else fails, be enigmatic."