Jessica Simpson -- Pre-Wedding BBQ at Uber Fancy Resort

Jessica Simpson treated her wedding guests to an awesome 4th of July BBQ -- but they weren't in some random backyard, the group partied at one of California's most exclusive resorts.

The Simpson wedding is set to take place at San Ysidro Ranch in Montecito -- the same place JFK and Jackie O famously honeymooned. The guests celebrated our independence in style yesterday at the Santa Barbara adjacent resort.

The party included karaoke and a performance by a live band.