Cynthia Nixon had to be "thin and look great all the time" on 'Sex and the City'.

Cynthia Nixon

Cynthia Nixon

The 50-year-old actress - who played Miranda Hobbes in the iconic US TV series - thinks Lena Dunham's 'Girls' portrays women in a much more "real" light and is much grittier and darker in tone than her show was.

Asked which show has changed the game for actresses, she said: "I think 'Girls' is really important. When sex was bad on 'Sex and the City', it was funny. And the worse it was, the funnier it was.

"But when sex is bad on 'Girls', it can be really hard to watch, and it's sometimes abusive, and it's important to show

that.

"Plus, in 'SATC' we had to be thin and look great all the time; in Girls, they have permission to be more real and less airbrushed."

And Cynthia - who has kids Sam, 20, and Charles, 14, with ex-partner Danny Mozes, and son Max, five, with wife Christine Marinoni - admitted working on the HBO series forced her to think more about her appearance than she ever had in the past.

Discussing her most pivotal role, she told Net-a-Porter's magazine The Edit: "'Sex and the City'. In terms of everything, but especially in how it made me view myself and how other people viewed me.

"I'd always worked happily without focusing much on the way I looked, so it was like a whole undiscovered country."

The actress has most recently won critical acclaim for her role in 'Killing Reagan' and she thinks the show is proof that the TV industry is overtaking film as the most exciting entertainment medium.

She said: "A couple of decades ago, some of [today's] shows would have been movies, no question. But there isn't the same appetite for making an interesting, literate film.

"When I was told 'Killing Reagan' was for the National Geographic [channel], I thought, 'Don't they make panda movies and stuff?' But it has the budget and the viewership."