Mad Men actor Jon Hamm is among celebrities supporting Barack Obama's It's On Us campaign, which aims to help raise awareness of and prevent sexual assault on college campuses.

Hamm is joined by Ryan Seacrest, Mayim Bialik, Randy Jackson, Rose Byrne and Kerry Washington, starring in a public service announcement promoting the initiative, and comments 'It's on us to do something, anything, to keep an assault from happening'.