The actual ceremony will be held Monday night at an undisclosed location, and according to the source, not even the guests know where they're going just yet.

They're all being picked up from a location in Cannes and driven to the wedding venue.

Last month, Avril told E! News she and her hubby-to-be wanted their wedding to be very intimate.

"We want it to be unique and special and we it to be a very big event but at the same time it's small and it's just close friends and close family," Lavigne said.