From Wikipedia:Robert Martin Culp (August 16, 1930 – March 24, 2010) was an American actor, scriptwriter, voice actor and director, widely known for his work in television. Culp earned an international reputation for his role as Kelly Robinson on 'I Spy' (1965–1968), the espionage series in which he and co-star Bill Cosby played a pair of secret agents. Prior to that, he starred in the CBS western series, 'Trackdown' as Texas Ranger Hoby Gilman from 1957-1959.
The 1980s brought him back to television, starring as FBI Agent Bill Maxwell on 'The Greatest American Hero'. He also had a recurring role as Warren Whelan on 'Everybody Loves Raymond'. In all, Culp gave hundreds of performances in a career spanning more than fifty years.
AS SEEN IN:
'Law And Order'
Culp was the TV Western inductee in 2010, the year he died. The "honor" was for his role as Hoby Gilman in 'Trackdown'.
When Lennie Briscoe sees that it's Culp who is jogging with their suspect, he says to his partner Rey Curtis that it's "What's His Name", that he starred in that TV series with Bill Cosby. When Curtis asks which series, Lennie brushes him off by saying that it was before his time.
So there is no mention of 'I Spy', so it could be a fictional TV show from Toobworld in which the two starred. Or maybe they were cast in a version of 'I Spy' which fictionalized the activities of Kelly and Scott so that there could be deniability that they actually existed if necessary. (As was the case with James Bond, the U.N.C.L.E. agents, and the Time Lord known as the Doctor.)
Maybe their TV show was "Hickey And Boggs", and the movie we saw was a combination of a two-parter.