Kristin Cavallari wasted no time losing the baby weight!
The 25-year-old former Hills star welcomed her first child, son Camden, with fiance, Chicago Bears quarterback Jay Cutler, 29, on Aug. 10.
PHOTOS: Kristin's sexy maternity style
Just five weeks after giving birth, Cavallari "has already lost all the weight by working out like crazy with a trainer," a source tells Us Weekly.
Last week, the reality star tweeted, "Walking uphill on the treadmill to work out this booty. Bye bye baby weight."
PHOTOS: Kristin's best bikini moments
While Cavallari has had no problems losing the weight, there is one thing she's struggling to change after becoming a mom.
PHOTOS: Celebrity pregnancies
"Still need to work on my potty mouth," she tweeted on Sept. 15. "Swearing just comes so naturally to me."
This article originally appeared on Usmagazine.com: Kristin Cavallari "Has Already Lost All of Her Baby Weight"
Get the scoop on Bradley Bayou's dress design that Oprah wore to the Emmy Awards.
See where Hollywood's A-listers have spent the summer.
Get Mariah and Nick's marital woe breakdown on Replay hosted by Wonderwall's Kirby Kristen.
Jennifer Lopez reunites with Casper Smart, plus more famous friendly exes on Replay, hosted by Wonderwall's Jessica Wedemeyer.
Get the scoop on Ashlee's new fiance on Replay hosted by Wonderwall's Kirby Kristen.
Check out some of the most memorable Emmy fashion from over the years.
Check out the many sexy bikinis Jessica Alba has rocked over the years.
© 2014 Microsoft