The Cosby Show Wiki
I Know That You Know
Season 03, Episode 21
Air Date March 19, 1987
Writer John Markus
Carmen Finestra
Matt Williams
Director Jay Sandrich
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I Know That You Know is the twenty-first episode of The Cosby Show's third season which was first broadcast on March 19, 1987.


Theo receives a package of practical jokes in the mail and succeeds in fooling Clair, Vanessa and Rudy. But Theo's gags cannot fool Cliff and he brags that he is too clever to be tricked. Later, when Cliff is out, Sondra and Elvin visit the family to announce their engagement. The Huxtables decide to use the exciting news to play an elaborate joke on Cliff.