X17 EXCLUSIVE - Nicole Richie's Wedding Prep Crew: We Signed A "Strict Confidentiality Agreement"

If you think the crew working on Nicole Richie's upcoming wedding will spill any details about the Beverly Hills ceremony, think again.

Crews from Rene's Van and Storage and Revelry Event Designers have been seen bringing equipment and furniture to the home of Nicole's dad, Lional Richie ... and all of them have been sworn to secrecy.

An employee of Rene's tells X17online exclusively:

"Our hands are tied on this one. We signed a very strict confidentiality agreement. When a contract is drawn up, we're bound by that and if we talk, it could cost us a lot more than our job."

As for the vibe of the wedding, sources close to the couple tell us exclusively that Nicole and Joel have requested rental furniture from Revelry Event Designers with a "vintage and earthy" vibe. Also on the list of rentals ... "lots of wood pieces and leather." The wood tables that have been chosen for the event will cost an estimated $700 per piece to rent.

With all this secretive planning going on, let's hope the happy day goes off without a hitch.