Though Simpson is currently expecting her second child with fiance Eric Johnson, it sounds like the mom-to-be still had a good time partying with her BFF.
The ladies and a small group of their friends celebrated at the Bel Air hotel on Thursday, Dec. 13, a source tells Us Weekly.
Simpson, 32, was "drinking sparkling water and the group dined on fried chicken," the eyewitness tells Us.
But the Bachelorette party wasn't as tame as it sounds. The girls did decorate for the occasion with penis-themed props!
On Cobb's big day, however, decorations were more traditional. "She was the most beautiful bride I have ever seen in my life!" Simpson tweeted Sunday.
The Fashion Star mentor served as the maid of honor in a black gown that showed off her baby bump. "She held her bouquet of red flowers in front of her stomach most of the time," an observer told Us. "She seemed bigger in the belly, but her dress was loose enough that her pregnancy wasn't too obvious."