Beyonce, Jennifer Aniston, Reese Witherspoon and Gwyneth Paltrow are among the stars who have recorded a special video message demanding a new plan for gun law reform.
Suspected gunman Adam Lanza, 20, opened fire at Sandy Hook Elementary School in Newtown, Connecticut last week (14Dec12), killing 20 young children and six adults, before allegedly turning the weapon on himself.
The massacre is the latest tragedy to rock America in recent years, following shootings at Colorado's Columbine High School in 1999, Virginia Polytechnic Institute and State University in 2007, and a movie theater in Aurora, Colorado in July (12).
And in the video, celebrities also including John Legend, Cameron Diaz and Selena Gomez, take turns asking when the violence will end and urge viewers to call for change.
The somber black-and-white clip was released on Friday (21Dec12) - exactly one week after the Sandy Hook massacre - to coincide with the launch of Demand a Plan, a new movement which seeks to ban the sale of assault weapons, among other things.