JESSICA SIMPSON'S new BOYFRIEND!!!

On its Web site, Hollywood's fabled Chateau Marmont hotel boasts that its "thick soundproof walls...ensure privacy." But if a recent guest's experience is any indication how soundproof those walls are may depend on who's behind them — and what they're up to!

"My friend was staying for a few days over the weekend of Feb. 3," a source tells Star. "One night, an amazing couple walked into the room next door — it was Jessica Simpson and Jude Law! My friend had seen them around the hotel over the entire weekend — but to see them going into the same room together was a shock!"

NOISY NEIGHBORS
It wasn't the only shock of the night, as it turned out! Around 2 a.m., according to the source, the guest was wrenched out of a deep sleep and had to call downstairs to the hotel's management to ask for a change of rooms. Why? "She told me the people next door were very loud," the source says. "She told me, 'There was banging on the wall and loud noises behind my bed. It lasted half an hour, and it was impossible for me to get any sleep.'

"My friend didn't know if they were having a party, were dancing or what was going on. She thinks Jessica and Jude are both hot. But she needed to get some rest and not hear two people next door pounding on the wall in the middle of the night, sounding like they were tearing each other up. The hotel's management finally apologized and changed her room — even as the noisy antics went on!"

The next day, the source says, "My friend looked exhausted." She probably wasn't the only one!