David McCallum in Bert D'Angelo/Superstar

 In 1976 David McCallum appeared in one episode of the 11 episode series Bert D'Angelo/Superstar, described on IMDB as 'the action-packed cases of maverick San Francisco cop Bert D'Angelo.'  David McCallum played a character called 'Cobb' in episode six, 'A Noise in the Streets.' The episode description, from another site, runs as follows: The death of a famous geologist in the restaurant of a luxury hotel puts D'Angelo on the trail of a dangerous international hit man and his girlfriend. The pair take refuge in a church and hold a priest hostage. Presumably David McCallum plays the international hit man. And now you know as much as I do. The only other thing I know is, damn he's hot in 1970s demin with long hair and ribbed flared jeans.