According to the AP report, the Metropolitan Opera sent an e-mail message to its board members this week saying that Sills is "gravely ill." Sources told the AP that she is in a hospital with her daughter at her bedside.

Sills underwent surgery and treatment for breast cancer in 1974 and made a complete recovery (as her subsequent careers demonstrate). She is reportedly a non-smoker.

The 78-year-old Sills, a native of Brooklyn, made her first opera appearance in 1947 and eventually became a world-renowned coloratura soprano and singing actress, as well as a public spokesperson/cheerleader for opera and the performing arts in general. She also became a beloved television personality, appearing regularly on the small screen with such stars as Johnny Carson, Carol Burnett and the Muppets.

After her retirement from the stage in 1980, she became a highly successful administrator and a major power in the New York cultural world: she steered New York City Opera, the company where she became famous, through several crises and stabilized the institution as its general director in the 1980s; she then served as chairman of Lincoln Center and later of the Metropolitan Opera, where she (among many other achievements) raised the cash to save the weekly radio broadcasts after longtime sponsor Chevron Texaco withdrew its support.

Sills stepped down abruptly from the Met chairmanship in January 2005, reportedly due to problems with her own health and that of her husband, who died last September. She has continued to make occasional public appearances until quite recently, such as hosting several of the Met's new high-definition simulcasts into movie theaters this past winter and spring.