Kristin Cavallari showed off her impressive slim physique on Wednesday, July 23, two months after giving birth to baby son Jax. Credit: NATIONAL PHOTO GROUP

Hey little lady! Two months after giving birth, Kristin Cavallari ran errands in L.A. on Wednesday, July 23, showing off her impressively slim physique in a form-fitting cream color dress.

The Hills alum, 27, who welcomed son Jaxon in May with husband Jay Cutler, topped her petite frame and blonde hair with a black fedora. "Yesterday's #OOTD," Cavallari wrote Thursday on Instagram. "Riller & fount dress, kristin Cavallari by Chinese laundry shoes, the row backpack, and hatattack hat."

The star's tiny waist and toned arms result from her commitment to the gym, as witnessed throughout her second pregnancy and after giving birth. Cavallari recently shared a mirror selfie of herself, pumping weights, on Instagram. "Tired today..blah. At least l managed to do some legs and butt with ankle weights," she wrote.

The designer and her family are currently on the West Coast ahead of Cutler's NFL season. The California native, whose quarterback husband signed a seven-year contract with the Chicago Bears in January, tweeted Tuesday, July 22, that the "only good part about training camp is that I get to spend 3 weeks in LA."

In her new app, the former Hills star expressed how much she loves spending time with her hubby and their two sons — Camden, 23 months, and Jaxon, 2 months — during the quiet months of summer.

"The end of June through the end of July is my favorite time of the year," Cavallari wrote in a post, "because Jay isn't working and we use those 4 weeks to relax and spend as much time together as possible before he takes off for training camp and the football season begins."