The former Laguna Beach and The Hills star looked lovely as she posed in a bikini at her friend's bachelorette party in California on Sunday (14 June).
Kristin, 29, said she'd had the "best weekend" ever, joking: "Even though I was the first one in bed it was a blast!"
The reality star-turned-shoe designer is expecting her third child with American football player husband Jay Cutler.
They're already parents to sons Camden, two, and Jaxon, one.
Kristin told Fit Pregnancy magazine last year she wanted to have her family when she was still young, explaining: "It's cute to see Jay as such a great dad! We're excited to do this while we're young," she explains. "Then when the kids go to college, we can travel and do whatever we want.
"My husband tells me I was born to have babies because it comes so naturally to me. I think I'm a good mum in the sense that I'm loving and nurturing, but I also set boundaries. The hard parenting comes later when we deal with real-life issues. Banging on pots and pans is going to be the least of our worries."
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