Hollywood biggest celebrities and musicians are banding together against gun violence.

Jennifer Aniston, Jamie Foxx, Selena Gomez, Reese Witherspoon, Gwyneth Paltrow and Beyonce are just a few of the stars who are taking part in a new PSA for Demand A Plan ... a grassroots initiative that demands President Obama and Congress step forward with a plan to end gun violence.

In the video, the stars ask the following questions: “How many more colleges? How many more classrooms? How many more movie theaters? How many more houses of faith?”

The campaign was created following the school shooting in Newton, Connecticut that claimed the lives of 28 people, including 20 children.