The mum-of-two showed off her toned figure in a fitted fuchsia dress at the party, where she posed with her expectant pal for a sweet photograph.
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Jessica Simpson showed off her toned figure in a fitted fuchsia dress
Jessica has been vocal about her efforts to get back in shape following the arrival of her children, Maxwell and Ace, who was born last year.
The Weight Watchers spokeswoman has an added incentive – she's due to tie the knot with her fiancé Eric Johnson over the 4 July holiday weekend.
Jessica, 33, is thought to have upped her daily cardio workout to six miles a day on the treadmill to prepare for her wedding day.
Jessica Simpson has been working hard to be in the best shape for her wedding day
"Jess probably spends half the day there (in the gym)," an insider told Life & Style. "Jess has gotten her best bod ever. She truly feels like she's in better shape than she was in her early 20s."
The star is, understandably, delighted by the results of her hard work - and has been celebrating with lots of raunchy selfies.
Last month she showed off her body in two Instagram photographs, posing with her husband-to-be's golf clubs.
Jessica Simpson posted these two pictures last month, proudly showcasing her toned body
"If I'm in a bathing suit I should pose proudly," she wrote alongside one of the pictures, in which she is wearing just a swimming costume, heels and sunglasses.
In February, Jessica spoke candidly about gaining weight during her pregnancies. "It is a really hard thing to go through," she told ABC News. "And you deserve to eat ice cream, you deserve to have your pancakes. Do whatever you want to do and then afterwards just know that you have to work really hard.
"I had to learn that with my first and second pregnancy. My first pregnancy I ate a lot more, but my second pregnancy I ate enough, like I ate what I wanted to eat but I stayed active and I think because I had gained so much weight with my first that I had to stay active throughout my second because I didn't know what to do with myself if I didn't."