Actress Julianne Moore is urging Americans to wear orange on Friday to mark National Gun Violence Awareness Day.

Moore got involved in campaigning for an end to gun violence after the 2012 shootings of 20 children at Connecticut's Sandy Hook elementary school, and she is now chair of the Everytown Creative Council.

"When our federal government failed to act I was really shocked and that's when I realized that I was not being a responsible parent or a citizen by not becoming involved in an issue I cared deeply about," Moore said on Thursday.

New York's Empire State Building will be lit up in orange on Friday to mark gun violence awareness.