The Weekend Australian reported Saturday that Roberts made a deal with Depp for $2 million to have the U.S. actor produce and star in an adaptation of his book, "Shantaram."
Roberts is a former heroin addict who was convicted of armed robbery for using a toy gun in several hold-ups during the 1970s.
His novel, "Shantaram," was inspired by events in his life.
"It was an extremely humbling experience to have great actors wanting to play the part of a character you have created, a huge compliment," Roberts told the Australian. But in the end it was the level of artistic commitment to the project, particularly from Johnny and his producer Brad Grey, that I found to be profoundly inspiring."