"Can't a girl have a night out in Las Vegas with her sister without fake stories being posted?" Hilton pondered via Twitter Monday. "That story is a ridiculous lie. 100 per cent FALSE."
UsMagazine.com said Hilton has been dating "The Hills" co-star off and on since early 2009.
Newt Gingrich fires back at Mandela backlash
N.J. man wakes up from 10-hour sleep with knife in back