Nicole Richie Is A Diva

Paris Hilton has always been the prime prima donna on the set of E!'s "The Simple Life" -- until now. Sources on set tell TMZ that this time around, toothpick Nicole Richie also got all divalicious during taping of the show's fifth season.

During the shoot, we're told Nicole constantly showed up late, and upon swanning in would impose a deadline on producers, saying "You've got me for an hour or two."

Our sources also say that Richie upped her unreasonable behavior to another level during the final shoot of the season, when the all-important "show open" was being taped. Nicole turned up "several hours late" with boyfriend Joel Madden, and then gave producers another impossible deadline. After a serious blow-out argument, we're told producers had to call her agents just to get her to stay on-set.