"This pelt-wearing party girl is all animal skin and bones," said PETA. "She's an incredible shrinking woman with the heart to match," US Weekly reported Tuesday.
Ashley Olsen, 20, came in at a close second on PETA's worst dressed list.
"Wearing fur does add 20 pounds," PETA said, "but if Ashley wants to fill out her frame, we suggest using a fork instead."
PETA also took a snipe at "Desperate Housewives star Eva Longoria, 31, by saying, "You'd think she'd be more sympathetic to the plight of rabbits considering the way she screws around like one on Wisteria Lane."
Heiress Paris Hilton topped last year's worst dressed list from PETA, but reportedly stopped wearing furs after viewing a PETA video about the fur industry.
A spokesman for the group said they are taking a "wait-and-see" attitude before asking the heiress to join their "I'd rather go naked than wear fur" campaign.