9:37 AM PT -- A source close to Pierce Brosnan tells us the man never made it inside the home, or in the laundry room, instead, using an outdoor shower.
Gross moment at Pierce Brosnan's house ... police say a man urinated and defecated in his neighbor's yard ... then got on the actor's property and used the laundry room to wash up.
Law enforcement tells TMZ ... L.A. County Sheriff's deputies rushed to Pierce's Malibu estate Monday afternoon after getting reports of a man on his and his neighbor's properties.
Deputies say the guy was seen using the neighbor's backyard as his own personal bathroom ... dropping a deuce and rocking a piss ... before rummaging around the garbage and then moving over to Pierce's place.
Cops say the man walked around Pierce's backyard before heading to the front ... and then he made his way inside a laundry room, apparently using the Brosnan's water to clean himself.
We're told the guy took off when cops rolled up, heading down toward the beach.
The guy didn't get far ... we're told a Sheriff's helicopter found the dude hiding in the rocks along the coast ... he was taken into custody and booked for burglary ... for stealing Pierce's water.
Cops say Pierce's wife, Keely, was home during all the commotion ... but it's unclear if the 'James Bond' star was there too.
Originally Published -- 1:00 AM PT