"On March 15, 2014, the world will wake up to the third anniversary of the bloody conflict in Syria," says Elba's voice, as the song The Blanket of Night by British band Elbow plays in the background.
The YouTube clip:
The video, titled #WithSyria, reminds the world that this is "a crisis which has forced almost half the population from their homes."
- UN reports: Chemical weapons used in Syria are from army stockpile
- Report: Israel paying Syrian rebels for information
- Syrian exporters try to revive businesses in war-torn home
It also features Banksy's iconic image of a girl holding a red balloon, who floats past images of bombed-out buildings, bloodied bodies and ruined landscapes, before she is joined by one, then two, then hundreds and thousands more people, each holding a red balloon, until they cover the whole world.
"Will we let the people of Syria lose another year to bloodshed and suffering?" asks the voice of Elba. "Will you stand with Syria?"
The video concludes with the eponymous hashtag and the address for the campaign: withsyria.com.
The opposition Syrian Observatory for Human Rights says more than 136,000 have been killed since the revolt against Syria President Bashar Assad began in March 2011.
On Wednesday, United Nations Secretary-General Ban Ki-moon appealed to Russia and the United States to help revive stalled peace talks aimed at the civil war.