African-American civil rights groups say they plan to protest outside the Oscars show, where every single one of this year's 20 acting nominees is white.
However small, the demonstration on Sunday will revive debate about diversity at the Oscars-awarding Academy of Motion Picture Arts and Sciences, whose voting members are overwhelmingly white and with an average age in their 60s.
"The goal of the protest is to send a message to the Academy, send a message to Hollywood, send a message to the film industry," said Earl Ofari Hutchinson, head of the LA Urban Policy Roundtable group.
"And the message is very simple: you don't reflect America, your industry doesn't reflect America. Women, Hispanics, African-Americans, people of colour (are) invisible in Hollywood."
Halle Berry and Denzel Washington were famously lauded as having made a breakthrough for winning best actress and actor Oscars in 2002, but while there has been some progress in the decade since, it remains too little.
Critics rounded on the Academy as soon as the nominations were announced last month, with all-white acting categories for the first time in nearly two decades: the last time was in 2011, and before that, 1998.
Notable snubs included Britain's David Oyelowo, widely tipped for playing Martin Luther King Jr in Selma. The film's director Ava DuVernay was also left out, although the movie is among eight picture nominees.
The Academy has defended itself. Its first African-American president, Cheryl Boone Isaacs, said shortly after nominations were unveiled that they spurred her to accelerate reforms to make the Academy more inclusive.
Sunday's diversity protest is planned to take place only minutes before Hollywood's finest begin taking to the red carpet for the pre-show fashion parade, and barely three hours before curtain up on the 2015 Oscars.