She's feeling good!

Jennifer Hudson -- now a size zero -- turns 30 on Monday.

When the Chicago native appeared on American Idol in 2004, for the first time, she felt overweight.

"I didn't even know I was considered plus-sized until I came to Hollywood," she revealed in the September issue of Self magazine. "I thought I was the perfect size!"

At the time, the powerhouse singer was a size 16 -- a stark contrast to her uberthin competitors.

Since then, Hudson has dwindled down from a size 16 to a size six. In 2010, she became the spokeswoman for Weight Watchers.

"I'm prouder of my weight loss than my Oscar!" she said.

Tell Us: What do you think of Jennifer's slim physique?