Miss Duff opens up for the January 2008 issue of Cosmopolitan.

On marriage: “I’m definitely not ready to get married,” Duff, 20. “I think a reason that people in this business get married young is that they feel like everything comes to them sooner in life. It’s normal to be like, ‘Okay, what’s next?’ “

Having famously dated Good Charlotte musician Madden for 18 months – before they broke up in November 2006 – Duff is currently dating NHL player Mike Comrie.

On weight & body image: “You lose some happiness when that’s all you think about,” Duff says. “There definitely was a time, about a year and a half ago, when I was pretty obsessed with my body and my weight, but I’m better not stressing about my body all the time.”  She adds, “It’s not attractive when girls get super-skinny. Guys don’t like it. Girls don’t like you as much.”Next year, H. Duff will be tackling her first serious movie role in “War, Inc.”, co-starring John Cusack.  This year she spent promoting her latest CD, Dignity, which hit stores in April.

Interesting pairing for a serious movie … but I love me some John Cusack, so I’m in.  Swoon.

Click here for the trailer to “War, Inc.”!