The event will be aired live on television on 22 January, commercial free across several major US networks, as well as internationally via MTV, CNN International and National Geographic.
Clooney will host the event in Los Angeles, with Jean in New York City and CNN's Anderson Cooper in Haiti.
Justin Timberlake, Bono, Alicia Keys, Sting and Christina Aguilera are billed to perform.
"Hope for Haiti" will be produced by Joel Gallen, who runs Tenth Planet Productions. He previously organised "Tribute to Heroes" 9/11 telethon in collaboration with MTV Networks and George Clooney.
All proceeds from the event will be split evenly among Oxfam America, Partners in Health, the Red Cross, UNICEF and Yele Haiti Foundation.
Social networking sites Facebook and MySpace have signed on as official social media partners.
Clooney has previously been involved with charity events, including the January 2005 Tsunami Aid telethon for the victims of the Asian disaster.
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