03/27/2012 AT 5:55 AM ET
After celebrating their baby shower last weekend, Jessica Simpson and fiancé Eric Johnson had another busy weekend at the Palm Springs wedding of Simpson’s friend and former assistant, Lauren Zelman, to Breaking In actor Bret Harrison.
The wedding festivities started on Friday with a rehearsal dinner at Las Casuelas Nuevas restaurant in Rancho Mirage. Wearing a floor-length emerald-green dress with jeweled platform sandals, “Jessica looked stunning,” a source tells PEOPLE. “She was moving very slowly and Eric held on to her tightly so she wouldn’t trip in her shoes.” The singer gave a toast to the couple, and “everyone seemed to have fun,” the source continues.
On Saturday, Simpson and her sister Ashlee were bridesmaids in the sunset wedding ceremony, which took place in the garden at the Parker Hotel.
According to an eyewitness, “Jessica was escorted down the aisle by a wedding coordinator so she wouldn’t fall. It was difficult for her to get around, but she was a great sport and kept smiling. Everyone at the wedding was doting on Jessica and seemed very understanding. And Lauren seemed very happy that Jessica was able to be a part of her wedding. ”
Also in the bridal party was Ashlee’s 3-year-old son Bronx Wentz. “Bronx was the ring bearer,” the eyewitness adds. “He broke down in tears several times, but Ashlee was great and kept making him smile again.”
Other wedding guests included actors Adam Brody and Josh Schwartz, who were groomsmen, plus Simpson’s best friend CaCee Cobb and her fiancé, Donald Faison. – Pernilla Cedenheim