The track will raise funds for charity Save The Children's Nepal Earthquake Appeal.
Wood said he was "delighted" to be able to take part in the recording, which features Knight on lead vocals and Jagger on backing vocals. They are accompanied by a 100-strong assembled choir of the charity's supporters.
"The terrible events in Nepal show just how vulnerable our fellow man can be in the face of nature," Knight said.
"My hope is that the proceeds of this song will go some way to help raise urgently needed funds to repair homes and restore lives."
The track was produced by Pink Floyd drummer Nick Mason.
More than 7,500 people were killed and hundreds of thousands left homeless by the quake, which struck on April 25.