It has been performed in several cities including New York, Los Angeles and Melbourne. Actors from each city sign on to be a part of the play, which is performed only once in each place.
George Clooney, Brad Pitt and Jamie Lee Curtis were some of the stars involved in the Los Angeles performance in April.
Last night's 21-strong cast included such well-known NZ performers as Robyn Malcolm of Outrageous Fortune, Ben Barrington of Almighty Johnsons and comedian Raybon Kan.
Celebrities invited to the reading, held at Auckland's Maidment Theatre, included Hottest Home Baker judge Colin Mathura-Jeffree and Shortland Street star Shavaughn Ruakere.
Tickets to the play were available at no cost and had all gone by last Friday.
People were asked to donate a small amount for attending, with proceeds going to Rainbow Youth - a support group for young homosexuals - and Afer.
The case, regarded as a legal landmark in the United States, is expected to be the subject of an appeal to the Supreme Court in Washington.