PIC: Slim Kristin Cavallari Stretches During Post-Baby Workout

Kristin Cavallari on September 26, 2012 in Los Angeles, California. Michael Simon/Startraksphoto.com

Bye bye baby weight, indeed!

Leaving son Camden, Kristin Cavallari enjoyed a workout outside in Los Angeles on Wednesday. The 25-year-old first-time mom went makeup-free and gave a big smile to photographers as she stretched.

Cavallari showed off her long, lean legs in Zaggora Viva HotPants (retail $80), but wore a loose-fitting gray shirt on top. The workout pants are specially designed to enhance your natural body temperature by up to 18% to help burn more calories. The former Hills star also flaunted her gorgeous engagement from Camden's dad Jay Cutler during her stretching.

The 29-year-old Chicago Bears quarterback and Cavallari welcomed their first child together on Aug. 8. The couple became engaged in April 2010, but briefly called off their engagement in November 2011.

Since giving birth, Cavallari has been working hard to shed the baby weight. "Walking uphill on the treadmill to work out this booty," she tweeted Sept. 13. "Bye bye baby weight."

On Sept. 22, the proud mom shared some adorable photos of "Cam." In one shot, she dressed her son in a Chicago Bears jersey. "He's so excited about this win he can't contain himself," she joked.

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