Well, to make a long story short, Wallace Shawn is Jewish!
Since Wallace Shawn's mother is Jewish, and in Orthodox Judaism and Conservative Judaism, those with a Jewish mother (or those who underwent a halakhic conversion) are considered Jewish, then that makes him Jewish. His father is Jewish too.
Wallace Shawn (whose full birth name is Wallace Michael Shawn) was born on 12 November 1943 in New York City, New York..
Shawn is best known for his part as Vizzini in The Princess Bride (1987), Mr. James Hall in Clueless (1995) and the voice of Rex in the Toy Story franchise. He has also had roles in six of Woody Allen's films.
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