"We're extremely pleased Ms. Johansson will join us for the Nobel Peace Prize Concert," said the Norwegian Nobel Committee's non-voting secretary Geir Lundestad.
"Her compassion and influence will help us tremendously in our mission of spreading the global message of peace."
Lundestad says the concert, televised in up to 100 countries, is the most popular event on the Nobel calendar.
Johansson, 23, will host a program headlined by Diana Ross. It includes Canadian singer Leslie Feist, who performs under the name Feist, American country singer Dierks Bentley, Mexican singer-songwriter Julieta Venegas, and Nigerian star Seun Kuti, according to a list released last week.
Johansson rose to stardom through her role in the 1998 film "The Horse Whisperer" and won the British Academy of Film and Television Arts best actress award for her role opposite Bill Murray in the 2003 film "Lost in Translation."
The Nobel concert is held a day after the Dec. 10 Nobel peace awards ceremony. Ahtisaari won the prize for his peace efforts on several continents over several decades.
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