Even if some people thought she carried a bit of added weight, Jordin Sparks was always pretty attractive to us. But the 22-year-old has really upped the ante now.

She reveals in the new issue of Shape magazine that she's dropped 50 pounds since winning "American Idol" in 2007, and is four sizes smaller to boot.

Need proof of just how dramatic the change to her body as been? Look no further than the cover of the mag, where she shows off in a bikini.

She says the call to drop weight hit her right before her 21st birthday, when she was diagnosed with walking pneumonia.

"I just wanted to be healthy,” Sparks says. “I remember thinking, ‘I’m in my prime. I should be happy and fit.’ That was the moment when I decided that changes needed to be made.”

Sparks says that eating poorly and not exercising enough contributed to her carrying extra pounds.

"I knew I had a long road ahead of me,” she says. “I was barely working out, and my diet was a mess. I had to address when, what, and how much I was eating.”

So she started watching her portions, selecting her food more carefully and hiking.

"The weight really started falling off, and I could see my muscles," she says. "It was awesome."

She credits her new body for her landing the starring role in "Sparkle," which hits theaters later this summer and co-stars the late Whitney Houston.

[NY Daily News]