The actress reveals she dropped from a size eight to a size two after realising she was too big to squeeze into outfits picked out for her Grace Adler character.
"When I started Will & Grace I was a size eight and what happened was, every time I would go in for a fitting, I couldn't fit into clothes," Debra told Jameela Jamil on her I Weigh podcast. "Eighty per cent of it, I couldn't fit into and I would just leave hating my body and hating myself."
"I loved my costume designer; she would always say, 'Don't worry,' and she would talk to her assistant and say, 'OK, can you call over and get a larger size?' And that was sort of the thing that was always on repeat all the time."
"So of course, I thought, 'My life would be so much easier, and it would be easier on everybody trying to do their job, if I just lost weight'. So I started doing yoga every single day and I did one of those meal delivery services. I started to get smaller and then I was a (size) six, and they were like, 'You're losing weight, you look amazing!' "
The message she heard "as a woman was, 'Oh, this is making them happy, so I should do more of it.' "
And then "Ally McBeal" stars Calista Flockhart and Portia de Rossi started to make super-skinny fashionable in Hollywood - and Debra felt too big again, "I would try to fit into these gowns and of course they weren't sample sizes and it was like, 'OK, we have to let out the seams...' "
"This was supposed to be the greatest time of my life... - I was standing next to all of these other actresses who were half my size, and I felt fat, and I felt ugly. I look back at those pictures and I was beautiful! I mourn the fact that that was my interpretation of reality and that was the torture that I put myself through."
"I was way too skinny... but I fit into everything... So all of a sudden, everything seemed to open up for me, because I was a (size) two."