The troubled star rented the luxurious four bedroom home in Venice Beach, Los Angeles, after completing 90 days at the Betty Ford Clinic, and she's telling pals she didn't know her DJ ex lived next door in an identical pad until she spotted her pulling into the driveway.
Lindsay has also been spotted hanging out at the same hotel as Sam, sparking more claims she's doing a stalker act on her ex.
"Its almost as if Lohan is pressing her, especially in light of her renting the beach house next door," an insider told the New York Post.
But just to prove she's not totally obsessed, Lindsay has ordered a fence to be built between the two properties.
A source told Radar Online, "It will give both of them some space and privacy, and it will ensure neither of them can see or spy on each other!"
After finding out that Lindsay was living next door, Sam reportedly said to photographers, "Trust me, it wasn't planned."