Kristin Cavallari was in rare form, and boy did she look marvelous in a bikini while she flaunted her baby bump for a friend's bachelorette party over the weekend.

"Had the best weekend for @char_major 's bachelorette! Even though I was the first one in bed it was a blast @chelseabulte @brookebaker_," the actress said in a post on her Instagram page.

You might have seen the former reality TV star in the 2012-2013 TV series "The League" or 2011's "The Middle," according to imdb.com. And she has done this all while married to husband of two years, Chicago Bears quarterback Jay Cutler, with whom she has three children, Camden, 2, and Jaxson, 12 months.

"We're at it again!" Cavallari said on her website, Us Magazine reported. "Thrilled to announce baby number 3 is on the way! The cutler crew just keeps on grown'!"