Dragon Ball Z - episode 72 - 18 Dec, 1990

Krillin and Gohan arrive at Frieza's spaceship and locate the Dragon Balls, unaware that Vegeta is not far away. As the two try to figure out what the password is, Jeice and Captain Ginyu, in Goku's body, arrive as well. The disguised Ginyu tries to trick Krillin into believing that he is Goku. Gohan, however, realizes that it is not the real Goku. Goku, in Captain Ginyu's destroyed body, arrives, and tells Krillin and Gohan what happened. Now it is up to Gohan and Krillin to defeat Captain Ginyu. (Source: Wikipedia)