Directors Dustin Lance Black and Rob Reiner were among the celebrities who showed their support for same-sex marriage by joining gay rights activists for a landmark hearing at the U.S. Supreme Court in Washington, D.C. on Tuesday (26Mar13).

The state of California passed the Proposition 8 bill to outlaw gay marriage in 2008, and on Tuesday America's highest court officials took on the case and considered the legislation's constitutionality during a series of opening arguments.

The Milk screenwriter and Reiner both travelled to the capital for the historic event and, in an early morning post on, an excited Lance Black, who penned a play about the controversial bill, titled 8, wrote, "Four years ago I stood on a very big stage and made an even bigger promise to the young people of this nation. That hopeful promise quickly turned to hard work and collaboration. In a few hours, I will walk into this nation's highest court to watch our team make the case to fulfill that promise of Federal Equality. Our time is truly now."

The Princess Bride star Reiner, who sits on the board of the American Foundation for Equal Rights, was also spotted in the court house, as was Jesse Tyler Ferguson's fiance Justin Mikita.

A number of celebrities were unable to make the trip, but they rallied behind the cause on - actress Kristen Bell, who famously pledged not to marry her fiance Dax Shepard until all couples could wed, wrote in a post, "today, the Supreme court is hearing 1 of the most important cases in history. dont (sic) sleep on it", while gay singer Ricky Martin also marked the historic day.