No baggy sweaters at her BFF's wedding!

Jessica Simpson proudly flaunted her baby bump in a form-fitting bridesmaids dress at CaCee Cobb's wedding to Donald Faison Saturday, Dec. 15.

As Us Weekly exclusively confirmed Saturday, Simpson's former personal assistant, 35, tied the the knot with Faison, 38, at Scrubs costar's Zach Braff's home in California after a sixteen-month engagement.

Simpson, who is expecting her second child with fiance Eric Johnson, served as one of Cobb's bridesmaids in a long black dress and carried a bouquet of red roses. The pregnant singer walked down the aisle with the help of groomsman Braff, 37. Simpson's separated parents, Tina and Joe, fiance Johnson, and her younger sister, Ashlee Simpson, also attended the ceremony.

On Sunday, Simpson tweeted, "I was the maid of honor last night for my BF Cacee Cobb. She was the most beautiful bride I have ever seen in my life!" She also shared a photo of herself hiding her bump behind her bouquet while posing with Johnson.

The bride looked stunning in a strapless white gown with a beaded bodice and floral skirt. Cobb wore her hair down and accessorized the look with a simple bracelet.

Braff shared several photos on Twitter to document his pal's special day. In one shot, Braff posed with the newlyweds at the reception during dinner.

The actor also tweeted a behind-the-scenes look from a photo booth at the wedding. The bride and groom, wearing a space helmet, posed for a silly shot with a sign that said "True Love."

"Knots tied," Braff captioned the funny shot. "No I did not run around them with sparklers . . ."

Source: US Weekly