The film has Hathway playing Maggie - a free-spirited but severely ill woman who gets involved in a love relationship with a Viagra salesman named Jamie played by Gyllenhaal, 29. Hathaway, most famous for her role in The Devil Wears Prada, had earlier come together with Gyllenhaal, and played a married couple in the romantic movie Brokeback Mountain in 2005.
"These are people who have no trouble taking their clothes off - in a way, their bodies are their currency. I was a wreck from start to finish. I think I cried every single day, I had to lean so much more heavily on everyone around me than I'm used to. I'm used to pulling my own weight. But I totally fell apart," Hathway added.
The movie Love and Other Drugs will be released in theaters on November 24.