Yikes!

A stalker was found residing at Jennifer Lopez's crib in the Hamptons – make that estate. Cops nabbed the stalker for crashing out in the singer's pool house. He went undetected for several days, which isn't a shock since the spread is massive -- an 8,500 square ft. property perched on three acres of land.

Authorities said that John M. Dubis, 49, took up residence in the pool house, which is located a ways away from the main dwelling of the $10 million crib, in early August. He moved around freely, hanging out in front of neighbors and brilliantly posted photos of himself on the grounds on his Facebook page. That's one way to get caught and caught he was on Aug. 8.

J. Lo was not home when her guest moved in.

The most surprising element of this story is the fact that there were security guards on site, patrolling the location. But they didn't notice the stalker. Somebody's gettin' fired.

Dubis was booked on charges of burglary, stalking and criminal contempt. Of course he entered a not guilty plea and in jail he sits, slapped with $100,000 bail. The judge ordered a mental evaluation, too.

This is the same man who contacted the mother of the singer/actress/possibly returning 'American Idol' judge earlier this year. She had a protective order against him. Yeah, that clearly worked.