Adrienne Maloof -- Moving On Up ... The Hill

Adrienne Maloof just inked a deal to lease a mega-mansion with an option to buy it ... for a pretty penny -- TMZ has learned.

Adrienne will be moving to a swanky, gated community in Beverly Hills adjacent, where Charlie Sheen, Paris Hilton and Slash call home.

The mansion is 10,000 square feet, 3 stories, with a theater, library and a backyard that looks like it sits in a resort.

Adrienne is leasing the crib for $20,000 a month, with an option to buy the property outright for a cool $6.5 million. You could say ... it's a downsize, because Adrienne and Paul just sold their even bigger mansion for $19.5 mil.