In the movie, Walker plays a man struggling to save his newborn baby girl in a New Orleans hospital during Hurricane Katrina.
The video, created before Walker's death on Nov. 30 in a car accident, has now become a poignant remembrance of the actor.
"When we made it, it was supposed to be a peek at the movie and Paul's extraordinary performance, then tragedy struck and suddenly it became a farewell," Safran says. "I still cannot believe he is gone. All we can do now is to honor his memory and keep his organization alive."
All profits from sale of the single will benefit Walker's organization, Reach Out Worldwide.