George Clooney and Brad Pitt in Proposition 8 courtroom drama

George Clooney and Brad Pitt have headed an all-star cast in a play about California's Proposition 8.

The play was written by Academy Award-winning screenwriter Dustin Lance Black and directed by Oscar-nominated director Rob Reiner, one of the founders of the American Foundation for Equal Rights.

Jane Lynch, who played Proposition 8 support Maggie Gallagher, said it was "amazing" to have Brad Pitt and George Clooney take part in the reading.

Jamie Lee Curtis said it was "exhilarating" to be part of the reading, adding "I found myself incredibly compelled by the story".