Rex Features
The Ghost scribe began working on the project, based on the bestselling novel by Audrey Niffenegger, before Pitt and Aniston divorced in 2005.
Speaking to OK, he said: "I thought they would be perfect for this film. I just saw them as a perfect version of Henry and Clare.
"I just found them equally attractive and equally compelling, and in terms of the Hollywood arena at that time, they were as good a couple as you could find. I was writing it in my mind for them."
Pitt and Aniston had initially owned the rights to the novel through their production company Plan B Entertainment, although the former Friends actress left the firm following their split.
The roles eventually went to Eric Bana and Rachel McAdams, who Rubin branded "wonderful embodiments of who I envisioned would be on screen".
The Time Traveller's Wife is released on August 14.
