AP Photo/John McConnico
U.S. actress Scarlett Johansson, right, and British actor Michael Caine, left, co-host the Nobel Peace Prize concert in Oslo, Thursday, Dec. 11, 2008. Artists from all over the world gathered at the Oslo Spektrum to help spread the message of peace and celebrate this year's Nobel Peace Prize laureate.
AP Photo/John McConnico
Actress Scarlett Johansson, left, reacts with Nobel laureate Martti Ahtisaari , during the Nobel Peace Prize concert, in Oslo, Thursday, Dec. 11, 2008.
AP/SCANPIX, Heiko Junge
Singer Diana Ross performs at the Nobel Peace Prize concert in Oslo, Thursday, Dec. 11, 2008.
AP Photo/Odd Andersen
Nigerian musician Seun Kuti performs at the Nobel Peace Prize concert in Oslo,Thursday, Dec. 11, 2008.
AP Photo/Odd Andersen
Mexican singer Julieta Venegas performs at the Nobel Peace Prize concert in Oslo, Thursday, Dec. 11, 2008.
AP Photo/Odd Andersen
U.S. singer Dierks Bentley, left, and Norwegian singer Marit Larsen, right, perform at the Nobel Peace Prize concert in Oslo, Thursday, Dec. 11, 2008.
AP Photo/Odd Andersen
U.S. actress Scarlett Johansson, center right, and British actor Michael Caine, left, co-host the Nobel Peace Prize concert in Oslo, Thursday, Dec. 11, 2008.
AP Photo/John McConnico
Members of El Divo perform at the Nobel Peace Prize concert in Oslo, Thursday, Dec. 11, 2008.
AP Photo/John McConnico
Scarlett Johansson and Michael Caine co-host the Nobel Peace Prize concert in Oslo, Thursday, Dec. 11, 2008.
AP Photo/Odd Andersen
Norwegian musician Magne Furuholmen of Aha backs singer Jason Mraz on piano at the Nobel Peace Prize concert in Oslo, Thursday, Dec. 11, 2008.
AP Photo/Odd Andersen
U.S. singer Jason Mraz performs at the Nobel Peace Prize concert in Oslo, Thursday, Dec. 11, 2008.
AP Photo/Odd Andersen
Swedish singer Robyn performs at the Nobel Peace Prize concert in Oslo, Thursday, Dec. 11, 2008.
AP/SCANPIX, Heiko Junge
U.S. actress Scarlett Johansson is seen on stage at the Nobel Peace Prize concert in Oslo Thursday Dec. 11, 2008.
AP Photo/Odd Andersen
Nobel Laureate Martti Ahtisaari, former President of Finland, left, Norwegian Crown Prince Haakon, center and his stepson Marius Hoyby, right, are seen at the Nobel Peace Prize concert in Oslo, Thursday, Dec. 11, 2008. Ahtisaari won the Nobel Peace Prize for his efforts to build a lasting peace from Africa and Asia to Europe and the Middle East.