Lindsay Lohan is best buds with her former nemesis Paris Hilton, and the two even had a sleepover in Las Vegas this weekend reports Pagesix.

On Saturday night, the terrible twosome arrived arm-in-arm to Michelle Trachtenberg's 21st birthday party at Tao and spent the night signing autographs for fans and whispering to each other. Then the duo retired to the $25,000-a- night Sky Villa at the Palms .

Earlier this month Paris Hilton rekindled her friendship with Nicole Richie. Now Nicole’s other friends tell Star that Paris is only returning to Ritchie’s side to try to maintain her rapidly fading chances at fame. Another friend says that it’s Nicole who’s in it for business, staging a friendship to boost ratings for the upcoming fifth season of The Simple Life.