Leaked photos of naked U.S. film actress Scarlett Johansson have sparked an FBI investigation into allegations that dozens of Hollywood celebrities have become victims of phone hacking.

Nude photos of the "Lost in Translation" star were published on U.S. gossip websites on Wednesday after they appeared on the Internet.

Johansson's photos were apparently taken by the actress herself with a cell phone. In one of the shots she is photographed lying down, with her left breast exposed. Another picture shows her reflection in the mirror showing her backside.

There were also reports of a hacked picture of Justin Timberlake, taken by actress Mila Kunis, and the FBI has investigated incidents involving Vanessa Hudgens, Jessica Alba and more.