Jessica Simpson and Eric Johnson are going to extremes to hide something -- like every inch of their bodies during their family vaca in Hawaii.
We've already seen Jessica covering up on the beach since announcing her pregnancy ... but during a Christmas Eve stroll on the beach even Eric was cloaked from head-to-toe while carrying baby Maxwell.
Far as we know ... Eric doesn't have a deal to drop lbs on Weight Watchers.
The only Simpson not in undercover mode these days is Ashlee Simpson ... who proudly showed off her bikini bum.
Click through the gallery ... she's worth the trip.