The video sharing website has launched what it is calling a "video petition", a new channel on YouTube where web surfers can post their personal video plea to end global poverty.
The campaign was launched in New York yesterday as world leaders, including prime minister Gordon Brown, gathered to discuss the United Nations Millennium Development Goals set in 2000 and aimed at ending global poverty by 2015.
The YouTube campaign is being launched in association with Oxfam, GCAP, Save the Children and Comic Relief.
As well as Will.i.am, John Legend, Scarlett Johansson, Fergie, Annie Lennox, Mischa Barton, Angelique Kidjo, Kristin Davis, Elle Macpherson and Jordan's Queen Rania are also joining the campaign.
From now through November 1, users can visit the channel to upload a video that includes their name, home country, and a simple message to their government about the need to meet the UN's Millennium Development Goals.
YouTube said on its blog: "Be as creative, compelling, simple, or wordy as you like -- this is your chance to join the video petition to end world hunger."
At the end of the program on November 1, a mash-up of the most powerful submissions from around the world will be broadcast directly to global leaders at the United Nations General Assembly.
Will.I.am sings: "It's calling individuals to realize their power in solving global poverty and ending world hunger.
"Enforcing the politicians to keep what they promised and picking the world leaders that will lead the world honest."
Kidjo said: "How can we continue this injustice and move forward, how can we prepare the next generation not to repeat the same mistakes that are happening today?
"As an African artist, as an African mother, as an African person I cannot just standby."
'Sex and the City Star' Kirsten Davis, who played Charlotte in the hit TV show, is an ambassador for Oxfam and spoke after the event saying that world leaders are ultimately responsible for the commitments they made to end poverty by the year 2015.
Davies said: "We're halfway through that mark. Those promises have not been kept in terms of the funding and what we are trying to say is that we are paying attention.
"We want the promises that were made in our name to be kept."