Justin Bieber and more celebs have signed on to support Beyonce and the global campaign for World Humanitarian Day, which is Sunday.

The campaign asks that on Sunday people help others through such acts as making sandwiches for the homeless or volunteering at a local charity. The goal is to share 1 billion messages of hope, reports SacramentoBee.com

A representative for Beyonce says that Justin Bieber, Lady Gaga, Michelle Obama, Rihanna, Shakira, Jay-Z, Gwyneth Paltrow, Chris Martin and others will participate.

Justin tweeted:

“I am supporting the UN for World Humanitarian Day. #WHD2012 whd-iwashere.org.”

Beyonce performed her song “I Was Here” at the United Nations in New York last week to promote World Humanitarian Day. The performance was taped and the music video will debut Sunday. The song is from her latest album “4.”

More info: whd-iwashere.org