Bieber, Gaga join Beyonce for campaign

Beyonce performs onstage during the filming of the "I Was Here" video at the General Assembly at the United Nations in New York, in this August 10, 2012 handout photo received by Reuters August 11, 2012.[Photo/Agencies]

Justin Bieber, Lady Gaga and Michelle Obama are giving a helping hand to Beyonce.

Obama and the pop stars have signed on to support the global campaign for World Humanitarian Day which Beyonce marked Sunday with the release of a new video for her song "I Was Here," filmed at the United Nations in New York last week.

Related Photos:Beyonce performs for filming of 'I Was Here' video

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.

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