(CNN) -- American fashion designer and film director Tom Ford has revealed he received angry letters from his predecessor and rival Yves Saint-Laurent.

Ford, 49, took over Yves Saint-Laurent's eponymous fashion house in 1999 when parts of it were sold to the Gucci group, where Ford was creative director.

And the designer says that while the pair started as friends, the relationship soon soured -- to the point that Saint-Laurent, one of the pioneering figures in 20th Century fashion, accused Ford of ruining his reputation.

Even in public comments, the Frenchman had made no secret of his disdain for Ford's taste.

"He was supportive at the beginning," Ford told CNN's Talk Asia. "He loved the fact that we were buying the company, and he loved the fact that I was designing, and he had been very complimentary of my work at Gucci.

"We were quite friendly, and had dinner a few times, and my first collection, I had him up to show it to him.

"Our business was doubling and doubling and doubling, and when I started to get great press and the business started to become very successful, Yves became really quite hostile.

"I have letters that he wrote to me about it, you know: 'In 13 minutes on the runway you have destroyed 40 years of my career.'

"I am really happy I have them -- they are written in his own hand. When I'm 85, maybe I'll put them in a book -- if anyone cares."

Ford left Gucci in 2004, before setting up his own label -- Tom Ford -- something he told CNN had previously frightened him.

"I guess what I feared was that with many designers, they sell their own labels, they lose control of their labels, perhaps things are then created which then go very much against their taste level.

"Your name is a funny thing. It stands for what you're about and everything I do is really about pride.

"I don't work for money any longer. I'm fortunate enough not to need to work for money, but I work for pride, I work because I love to work, and so the idea that one could lose control of one's own name and that things could be produced with your name on that you were not proud of scared me."

The designer has also broadened his career path in recent years, moving into film with the award-winning Christopher Isherwood adaptation "A Single Man," starring Colin Firth as a gay British university professor unable to cope in 1960s Los Angeles after the sudden death of his partner

Ford told CNN the shift towards Hollywood "felt totally natural."

"I know a lot of people in the film industry, and everyone was incredibly supportive. There's a line that people in Hollywood can 'nice you to death', so you have to take it with a grain of salt, but they were incredibly polite, incredibly supportive.

"It wasn't until after I had made my film that almost every interviewer said: 'What was it like, making a film and having it turn out as a success when everyone thought you were crazy?'

"And I thought 'People thought I was crazy? You mean people didn't actually think I could do this?'

"I had a very clear picture of what I wanted the film to be, and I'm not going to say that there weren't things that I learned and that I didn't know, but directing a film is not that dissimilar to being the creative director of a large fashion house.

"First of all, you have to have a vision; that's the most important thing. Why does anybody need to see a Tom Ford film? Why does anyone need a Tom Ford jacket? So you have to have something to say.

"Then you have to hire a great team of people to help you realize that vision, and you have to create an environment where those people can be creative, and give you their very best.

"Then you have to slowly guide carefully that team of people to help you realize your vision. So the dynamics of film directing and fashion design -- in the ways that I've done it -- were not dissimilar."

Saint-Laurent retired from the fashion industry in 2002, and died in June 2008 of brain cancer at age 71.