John Colicos
From Battlestar Wiki, the free, open content Battlestar Galactica encyclopedia and episode guide
John Colicos (b. December 10, 1928, d. March 6, 2000) was a Canadian actor who portrayed Baltar in the original series.
He is also famous for his role as Kor, a Klingon, the original Star Trek series, and repraising the role years later in Star Trek: Deep Space 9.