Dan Steinberg, Associated Press
From left to right, actress Yeardley Smith, actor George Clooney, and actor Martin Sheen take a bow during the curtain call at the Los Angeles premiere of the play "8" in Los Angeles on Saturday, March 3, 2012.

If any doubt remained about just how fully Hollywood's elite supports same-sex marriage, all uncertainty about the issue evaporated Saturday at the Wilshire Ebell Theatre in Los Angeles.

Brad Pitt, George Clooney, Martin Sheen, Jamie Lee Curtis and Kevin Bacon were among the Hollywood A-listers who participated Saturday in a one-night-only reading of "8," the new play by Oscar-winning screenwriter Dustin Lance Black ("Milk") that glorifies the ongoing legal fight to invalidate the Proposition 8 voter initiative that California voters passed in 2008.

"With George Clooney and Brad Pitt leading the charge, the gay-marriage play '8' had its L.A. debut Saturday in a splashy event that was part activist theater, part Hollywood in-party," the Los Angeles Times' Culture Monster blog reported. "The sky-high celebrity factor no doubt … made '8' feel something like 'Ocean's Eight.'"

"The play by (Black) made its Broadway debut last year in similar starry fashion," the Associated Press reported. "Saturday's benefit performance was broadcast live on YouTube, where director Rob Reiner said it drew 200,000 viewers. … Relying largely on transcripts from court proceedings, '8' introduces viewers to the couples who challenged the California initiative, the attorneys who argued their case and a bumbling witness who spoke out against them."

The Hollywood Reporter noted the event "benefited the organization attempting to overturn Prop. 8," and Pitt and Clooney were joined on stage by "dozens of Hollywood's same-sex marriage advocates, including Martin Sheen, Jamie Lee Curtis, Kevin Bacon, Jesse Tyler Ferguson (of 'Modern Family'), Jane Lynch (of 'Glee'), Matthew Morrison, Chris Colfer and George Takei."