George Clooney has confirmed he will star in the second one-night-only production of Milk screenwriter Dustin Lance Black’s Proposition 8 play.

The LA production of the show, titled simply ’8′, revisits the ballot measure which banned gay couples from marrying in California and its reversal by Judge Vaughn Walker last year.

Clooney said: “It is astonishing that gay and lesbian Americans are still treated as second-class citizens.

“I am confident that, very soon, the laws of this nation will reflect the basic truth that gay and lesbian people – like all human beings – are born equal in dignity and rights.”

Black said: “People need to witness what happened in the Proposition 8 trial if for no other reason than to see inequality and discrimination unequivocally rejected in a court of law where truth and facts matter.”

Stars who performed in the New York production of the play in September included Morgan Freeman and John Lithgow.

The play will run for one night only in March, with proceeds going to the American Foundation for Equal Rights .

The sponsors of California’s controversial gay marriage ban recently attempted to disqualify the decision of a federal judge, Vaughn Walker, because he didn’t declare that he was gay when he overturned the state’s gay marriage ban last year.

The issue is set to be revisited in the courts after gay marriage opponents were given leave to appeal the case last month.