Britney In, Elton Out

The sheets were still warm when Britney Spears slipped into her new Las Vegas pad -- because she didn't even wait 24 hours for Elton John to move out before swooping into the elegant suite.
Sources close to the singers tell TMZ ... Brit is going to be living it up in the 8,000 square foot paradise known as the Palazzo Suite at Rio while she's in Vegas. Elton lived there during his most recent Caesars Palace stint ... but TMZ says he moved out Tuesday night, and Brit was in by Wednesday morning.
Brit's new THREE floor suite comes with 24-hour butler service, two jacuzzis, an elevator, and furniture on loan from 17 museums around the world.