Now, they are to reunite for a panel discussion with their Heat director Michael Mann for a Q&A led by Interstellar director Christopher Nolan.
Hosted by the Academy of Motion Picture Arts and Sciences, the discussion is scheduled to take place on 7 September at Beverly Hills' Samuel Goldwyn Theatre following a 4K DCP restoration screening of the crime film.
Heat follows the cat-and-mouse rivalry between homicide detective Vincent Hanna (Pacino) and professional criminal Neil McCauley (De Niro).
Mann previously announced plans to write a prequel novel of the film; if anyone can get him to reveal more details on that, it's Nolan.
The event will also serve as British filmmaker Nolan's reunion with Pacino following their time working together on 2002 drama Insomnia alongside Robin Williams and Hilary Swank.
Nolan is currently hard at work on WWII drama Dunkirk which is set for a July 2017 release. His previous films include Memento, The Dark Knight and Inception, all of which made it into BBC Culture's poll compiling the greatest films of the 21st Century.
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