Bobby Fischer (white) vs Fidel Castro (black)?
In the the XVII World Chess Olympiad in Havana (1966) Castro was actually playing against Filiberto Terrazas of Mexico- however, when Soviet player Tigran Petrosian began to assist the Prime Minister , Terrazas asked the passing Fischer for a bit of help.
Here Prime Minister Castro is playing against Petrosian , in a simultaneous challenge.
