Beyonce and Selena Gomez are among a litany of stars that have lent their faces and voices to the gun control cause. The 'Love on Top' and 'Love You Like a Love Song' singers are speaking out in the latest 'Demand a Plan' public service announcement.

In the somber black and white clip, Bey and Sel express frustration with gun violence in the United States, saying, "Enough." The PSA, sponsored by Mayors Against Illegal Guns, asks, “How many more colleges? How many more classrooms? How many more move theaters? How many more house of faith? How many more shopping malls? How many more street corners? Enough. Demand a plan right now."

A total of 55 celebs are featured in the ad, which also lists the towns and cities in which mass shootings have occurred recently, including Newtown, Conn., Oak Point, Ore. and Aurora, Colo. More information about the Demand a Plan cause can be found at the organization's website.

Other pop faces who have spoken out or given back in light of the tragedy include Lady Gaga, who is promoting mental health awareness; OneRepublic, who are raising funds for the families of the victims; Mike Posner, who wrote a song for the victims; 'The Voice' singers and coaches, who performed a 'Hallelujah' tribute and Rick Ross, who expressed his grief and condolences at a recent concert.