Coldplay, Jay-Z and Rihanna will perform in London for one of the Help For Haiti telethon broadcasts.
The Grammy-award winners will join U2's Bono and The Edge, Jay-Z and Rihanna in London for one of the broadcasts, which will be shown around the world on Friday.
A jam featuring Kid Rock, Keith Urban and Sheryl Crow is taking place in Los Angeles, while New York will see Haitian-born rapper Wyclef Jean perform with Bruce Springsteen, Mary J Blige, Shakira and Sting.
Altogether, more than 100 stars from music, TV and film have signed up to help raise funds for the two-hour show, called Hope For Haiti Now: A Global Benefit For Earthquake Relief.
It is due to air commercial-free across a series of networks including MTV, VH1, CNN and HBO on Friday at 8pm US time (1am Saturday GMT).
Performances will also be available to download from the internet afterwards.
Organisers said all donations would benefit Oxfam America, Partners in Health, Red Cross, Unicef and Wyclef Jean's Yele Haiti Foundation.
Meanwhile singer Beverley Knight backed children's charity Plan International's appeal to help victims of the earthquake.
Beverley, who has sponsored a child with Plan in Haiti since 2003, said: "Like many people around the world, I have been moved and appalled by last week's tragic events in Haiti.
"Haiti holds a special place in my heart as I sponsor a child who lives there. The fact that my child is Haitian has really struck a chord with me and prompted me to support Plan's emergency appeal."