Madonna, Diana Ross and Maroon 5 are among the artists who have pledged to perform on a US TV special raising money for the victims of the tsunami.
Madonna is set to perform during the telethon
Actors including George Clooney, Kevin Spacey and Uma Thurman also agreed take part in the NBC telethon on 15 January.
Proceeds from the benefit show will go the American Red Cross to aid its relief efforts in Asia.
Latin American singer Ricky Martin is to visit Thailand on Wednesday to see the devastated region for himself.
He will be spending four days in the country, where an estimated 5,300 people were killed when the giant wave struck on Boxing Day.
"I know he wants to see the devastation because he's concerned about orphans," said Foreign Ministry spokesman Sihasak Phuangketkeow.
"I'm sure he will want to meet some of the orphans there in Phuket."
The People for Children charity, part of the Ricky Martin Foundation, campaigna against the exploitation of children by sex tourists and child trafficking.
Ricky Martin has campaigned for the protection of children
Also joining the number of recording artists pledging money to victims of the tsunami is actress and pop singer Hilary Duff.
The 17-year-old star of the TV show Lizzie McGuire is donating a portion of her sell-out concert tour to the Kids With a Cause charity, which fights poverty and neglect for children around the world.
"I, just like everyone else, have watched this terrible tragedy and feel so sorry for the children and the families who have lost so much," said Duff.
"I want to do everything I can to help those that have survived."
The UK will also be hosting a concert on 22 January, with artists including Manic Street Preachers, Eric Clapton and Jools Holland performing at the Millennium Stadium in Cardiff.
Tickets for the event sold out within days, and up to 65,000 people are expected to attend.