WHITE PLAINS, N.Y. -- Dana Reeve, the singer-actress who married the strapping star of the ''Superman" movies and then devoted herself to his care and his cause after he was paralyzed, has died of lung cancer, a year and a half after her husband. She was 44.
Although Mrs. Reeve had announced her cancer diagnosis in August, her death seemed unexpected. As recently as Jan. 12, she looked healthy and happy as she belted out Carole King's ''Now and Forever" at a packed Madison Square Garden during a ceremony honoring hockey star Mark Messier, a friend.
''Unfortunately, that's what happens with this awful disease," said Maggie Goldberg of the Christopher Reeve Foundation, where Dana Reeve had succeeded her husband as chairwoman. ''You feel good, you're responding, and then the downturn."
Mrs. Reeve, who lived in Pound Ridge, died Monday night at Memorial Sloan-Kettering Medical Center in Manhattan.
''The brightest light has gone out," said comedian Robin Williams. ''We will forever celebrate her loving spirit."
President Bill Clinton and Senator Hillary Rodham Clinton described Mrs. Reeve as ''a model of tenacity and grace."
''Despite the adversity that she faced, Dana bravely met these challenges and was always an extremely devoted wife, mother, and advocate," they said.
Christopher and Dana Reeve married in 1992. Life changed drastically for the young couple three years later when Christopher Reeve suffered near-total paralysis in a horse-riding accident and almost died.
In his autobiography, ''Still Me," Christopher Reeve wrote that he suggested early on to his wife, ''Maybe we should let me go." She responded, ''I'll be with you for the long haul, no matter what. You're still you and I love you."
Those were ''the words that saved my life," Christopher Reeve said.
For his remaining nine years, Dana Reeve was her husband's constant companion and supporter during the ordeal of his rehabilitation, winning worldwide admiration. With him, she became an activist in the search for a cure for spinal cord injuries.
''Something miraculous and wonderful happened amidst terrible tragedy, and a whole new dimension of life began to emerge," she wrote in a 1999 book, ''Care Packages: Letters to Christopher Reeve from Strangers and Other Friends." ''What we had yet to discover were all the gifts that come out of sharing hardship, the hidden pleasures behind the pain."
After her husband's death, Mrs. Reeve said she planned to return to acting. She had appeared on Broadway and on the TV shows ''Law & Order," ''Oz," and ''All My Children."
Her own diagnosis came the summer after her mother died of complications from ovarian cancer. From the start, Mrs. Reeve, a nonsmoker, expressed confidence she would beat lung cancer. And four months ago, wearing a long formal gown at a fund-raising gala for the foundation, Mrs. Reeve provoked wolf whistles from Williams and said she was responding well to treatment.
At about the same time, Mrs. Reeve taped a PBS show, ''The New Medicine," about how doctors are paying more attention to a patient's cultural values and lifestyle as part of treatment. In her introduction to the program, Mrs. Reeve said, ''It has become clear to me that high-tech medicine, with all its wonders, often leaves out that all-important human touch."
PBS said yesterday that the show will be broadcast as scheduled March 29.
Mrs. Reeves leaves her 13-year-old son, Will; two stepchildren, Matthew and Alexandra; her father, Charles Morosini; and two sisters.
Goldberg said that Will was ''in the loving care of family and friends."
No plans for a funeral have been announced.