The Dreamgirls singer first joined forces with the weight-loss program in 2010 when she was a size 12. She lost some 80 pounds and now fits into a size six.
"After four years of a successful and rewarding partnership, Weight Watchers and Jennifer Hudson are ending our official partnership, though we're confident Jennifer will remain a lifetime member," a Weight Watchers representative said.
"Jennifer's healthy lifestyle and successful weight loss has inspired so many -- from her friends and family to our members and staff, as well as people around the world -- and we know that inspiration lives on," the statement continued. "We will continue to support Jennifer in maintaining her healthy lifestyle and wish her the very best in her personal and professional life."
Hudson, 32, said in November that she had finally reached the weight at which she feels comfortable.
"I'm at the weight I want to be," she told Redbook. "But I hear all the time, 'Don't lose any more weight, you need to stop.' People are under the impression that I'm still losing but I'm not."