Kelly Lost 18 pounds.

Kelly Clarkson's weight loss is easy to explain - she's in love.

The curvy 'Stronger' singer has revealed she lost 18 pounds after meeting her fiance Brandon Blackstock - who popped the question to her last month after just nine months of dating - because she wanted to look good for him.

The 30-year-old popstar told the February issue of Cosmopolitan magazine: ''I lost 18 pounds. And I think that happens when you fall in love or date someone. If I'm going to be messing around, I gotta look good.

''There's not a fad diet. I was working with a trainer, and she said, 'You'd be amazed the amount of weight you can drop by halving your portions. I know it sounds crazy, but do it for two weeks and watch what happens.' I just cut back my portions, I stopped eating late at night, and I work out a little more than I used to, and I literally dropped 18 pounds in a month. I think it happens when you get really busy. But when I'm on my off-time - girl, those 18 might come back.''

The newly engaged starlet also insisted that she despite feeling the pressure to slim down she wasn't willing to go on a crash diet.

She said: ''I'm not willing to do that. I'm willing to work a little bit because I want to be a healthy individual - which I always have been. I've put on weight, but that's just what I'm happy with at that moment.

''Brandon and I both have bikes on the back of the bus, and we both love the outdoors. Once your lifestyle becomes more active, obviously you drop weight.''

© Bang Showbiz