Brad Pitt has narrated a BBC radio documentary about British '70s rock performer Nick Drake, who has developed an international cult following that includes Pitt himself. Drake who died in 1975 of a drug overdose at the age of 26, had recorded only three albums, none of which was a hit. The documentary is set to air on January 3, 2008. In a BBC Radio interview to promote the program, Pitt, who turns 44 on Dec. 18, acknowledged that his own pop stardom is likely to fade soon. "I figure I've got very few films left. Who knows how many I'll get to do now, so I want to do something I'm interested in. Otherwise, I don't want to bother. I think it's a younger person's game," he said. Pitt recently pulled out of the cast of Universal's State of Play because, he insisted, the script was not ready and, given the strike, there was no writer to polish it. (Universal has suggested it may sue the actor if it is unable to replace him quickly with a major star; it is in talks with Russell Crowe.)