Jan Hooks, who worked alongside some of the biggest "Saturday Night Live" stars ... died Thursday ... TMZ has learned. She was 57.Jan Hooks was such a talented woman.
We've learned she passed away this morning in New York City. Sources tell us Jan had been battling a serious illness.
Jan was part of the 'SNL' cast from 1986-91 ... the same time as Chris Farley, Mike Myers, Phil Hartman, Dana Carvey and Dennis Miller ... and was most famous for being half of the Sweeney Sisters ... and also for her impressions of Sinead O'Connor and Hillary Clinton.
It's hard to remember, but Saturday Night Live actually used to be funny.
Rest in peace.