Karen Duffy (born May 23, 1962) is an American model, television personality, and actress.
Born in New York City, she attended Park Ridge High School in New Jersey until she graduated in 1979. She followed this with a bachelors degree in recreational therapy from the University of Colorado. By 1989 she was modeling and appearing in television commercials and would become a VJ for MTV in the early 1990s as "Duff." Since then she has had small roles in a handful of films including Dumb & Dumber, and by 1999 she was working as a correspondent for controversial documentary film-maker Michael Moore on his television shows TV Nation and The Awful Truth.
Duffy was leading a relatively carefree youth in the heyday of her modeling career, partying with movie star friends such as George Clooney, when in 1995 she was diagnosed with the relatively rare disease sarcoidosis. In her case, this affected her brain (neurosarcoidosis), leaving her partially paralysed. She has so far battled it with a sense of humor, as is evident from her 2000 autobiography Model Patient: My Life As an Incurable Wise-Ass. She has explained, "I tried to write a book not for sick people, but for people with a sick sense of humor ... is not a typical book about illness."
After the diagnosis she continued to model for Revlon and married John Lambros in 1997. She has since had a son.