Among other entertainment industry heavyweights, Anne Hathaway, Martin Sheen, Jane Lynch and Ellen DeGeneres signed an open letter sponsored by Freedom to Marry, a New York-based group promoting same-sex marriage rights.
Just weeks after President Obama's administration announced it would no longer legally defend the Defense of Marriage act, his supporters want him to go further.
"Whether to end discrimination in marriage is a question America has faced before. It is a question that calls for clarity from the president," the letter reads. "We ask you to join us, and the majority of Americans, who support the freedom to marry."
The letter was also signed by moguls David Geffen and Bob Wright; former NAACP chairman Julian Bond; and Facebook co-founders Chris Hughes and Sean Parker.
Hughes, who is gay, worked for Obama's campaign in 2008, heading its enormously successful social media efforts. But in 2011, the climate is a bit different.