Hotel heiress Paris Hilton has branded her former best friend Nicole Richie "jealous" and has even written a song about the end of their friendship. THE SIMPLE LIFE stars mysteriously fell out in January 2005 and have refused to divulge the reason behind the rift. But Hilton insists the blame lies with Richie and has hit out at her envy in thinly-disguised track JEALOUSY - which will feature on her upcoming debut album. She tells Out magazine, "It's a song about any girl. Any girl has a girlfriend that's jealous of you. It's the meanest, most evil thing that can take over you. "I brought her (Richie) on The Simple Life, and all of a sudden she became this different person. She dropped her old friends and now she's someone else. "That's not the girl I know. That's similar to the lyrics in Jealousy."