"We're delighted to confirm that Pete Wentz and Ashlee Simpson were married this evening in front of family and close friends," said the spokesperson.
Simpson, 23, wore an ivory lace wedding gown by Monique Lhuillier accessorized with a diamond necklace and earrings by Neil Lane as she and Wentz, 28, exchanged vows in front of 150 guests at her parents' Los Angeles area home.
Dad Joe Simpson performed the non-denominational ceremony, while sister Jessica served as maid of honor.
Wentz's English bulldog, Hemingway, was the ring-bearer.
Guests included Jessica's boyfriend, Dallas Cowboys quarterback Tony Romo, Nicole Richie and Joel Madden, as well as actor Donald Faison with girlfriend CaCee Cobb.
Simpson told PEOPLE on Friday that she was never the type to dream about her wedding when she was growing up, but changed her tune once she got engaged.
"Now that I'm doing it, I definitely have that big dream. It kind of went more fairytale than I thought. I got really into it." Added Wentz, "She has this amazing imagination and to watch it take place is an awesome thing."
With the help of wedding planner Mindy Weiss, Simpson got her dream nuptials: The Alice in Wonderland themed reception featured a wedding cake by Sam Godfrey of Perfect Endings with a top hat, tea pot, stop watch and a pot of flowers on top. The elaborate centerpieces of black beauty roses were by Mark's Garden. Guests were served Rose Veuve Clicquot champagne followed by a sit-down dinner and dancing to a deejay.