The You're Beautiful singer forged an unlikely friendship with the actress, who played Princess Leia in the sci-fi series, and moved into her house in Los Angeles during the 2000s when he was recording his first album, years before she died in 2016 aged 60.
An autopsy revealed she had a deadly cocktail of drugs in her system including cocaine, ecstasy, alcohol and opiates, which caused her to suffer a cardiac arrest on a flight from London to Los Angeles.
Singer James Blunt had formed an unlikely friendship with actress Carrie Fisher. (Tracey Nearmy/AAP PHOTOS)
Blunt told fans at the Hay literary festival: "I just knew that the day before she died when she came back to my house and she'd been really mistreating her body and she'd just got the job again of being Princess Leia in the new Star Wars movies.
"So she's really on a high and positive but they had applied a lot of pressure on her to be thin, which is what they do, so she spoke about the difficulties that women have in the industry that men are allowed to grow old and women are not.
"She had to really put a lot of pressure on herself and started abusing drugs again.
"So by the time she got on the plane, she had practically killed herself. They said it was a heart failure but she had taken enough drugs to have a great party."
Fisher previously said she had been pressured to lose 16kg to reprise her role as Princess Leia in 2015's Star Wars instalment The Force Awakens, telling Good Housekeeping: "They don't want to hire all of me - only about three-quarters!
"Nothing changes, it's an appearance-driven thing. I'm in a business where the only thing that matters is weight and appearance.Â
"That is so messed up. They might as well say get younger, because that's how easy it is."
