It's Jessica Simpson's big day, y'all!

The beautiful bride celebrated the Fourth of July with friends and family yesterday at the San Ysidro Ranch in Santa Barbara, where she'll walk down the aisle today and tie the knot with fiance Eric Johnson.

The scene was idyllic as guests snacked on down-home American food served buffet-style under tents. Red-white-and-blue throw pillows were scattered throughout and American flags were hung in every tent.

A source tells us, "Jessica's such a southern, American girl that it makes sense that she's getting married the day after the holiday. It turned out so perfectly to have a weekend destination wedding in Santa Barbara in this beautiful place and to have everyone together for three days for hers and Eric's marriage. This is a total dream wedding!"

Dream wedding, indeed! Check out photos of the amazing property HERE.