Her publicist, Bob Merlis, confirmed the death in a statement. The cause was not immediately disclosed.
Prima and Ms. Smith’s act offered a seamless blend of anarchy and sophistication, with his sassy beast to her cool beauty. Their physical and musical chemistry brought them a mass following, hit records, and $25,000 a week on the Las Vegas Strip, and helped make Sin City, then a second-tier desert outpost, a major show-business destination.
They won the first Grammy Award for best performance by a vocal group for their 1958 version of ‘‘That Old Black Magic’’ and foreshadowed the popularity of Sonny and Cher, the husband-and-wife variety show team who played up insouciant banter and mismatched physicality in the 1960s and 1970s.
Ms. Smith’s musicianship was peerless — with a phrasing style that was clean and caressing — and she exuded sex appeal with her tight blouses and satin and taffeta gowns. No one’s idea of a matinee idol, the burly Prima was almost 20 years Ms. Smith’s senior. The New Orleans-born trumpeter, singer, and irrepressible stage performer was a combination of Louis Armstrong and Jerry Lewis.
He belched, gestured suggestively, and rewrote lyrics to emphasize their bawdy possibilities. As Ms. Smith sang a plaintive rendition of ‘‘I Got It Bad and That Ain’t Good,’’ Prima interjected in a raspy bellow, ‘‘I’ve got it good and it ain’t bad!’’
Ms. Smith, sporting her signature page-boy haircut, brought an imperturbably blithe spirit to the festivities, hewing to the melody despite Prima’s efforts to throw her off.
‘‘The less she did, the funnier it was,’’ music critic Will Friedwald wrote in the New York Sun in 2005. ‘‘Their act was a brilliant juxtaposition of maximalism and a minimalism: Prima would be practically climbing the walls and swinging from the light fixtures. She just stood there with a stone-faced expression.’’
Prima was the impresario, crafting Ms. Smith’s stage persona as sultry and playful. In a nod to the emerging interest in rock ’n’ roll, Prima hired a rhythmically propulsive backup band, the Witnesses, that included New Orleans tenor saxophonist Sam Butera.
They recorded albums for Capitol Records, recreating jazz and pop standards in an array of styles and tempos: swing jazz, ‘‘shuffling’’ upbeat jump blues, Italian tarantellas, and Dixieland.
The clowning belied marital and professional discord. Music reviewers began to notice Ms. Smith’s beguiling way with the Great American Songbook, asserting that she was the real musical draw of the two.
The attention aroused jealousies in Prima that worsened as Ms. Smith’s solo projects increasingly became commercial and critical hits.
She earned a Grammy nomination for her million-selling 1958 single ‘‘I Wish You Love,’’ featuring a high-energy Nelson Riddle arrangement. She also recorded duets with Frank Sinatra. ‘‘Everyone thought we were having a big romance,’’ she later told the San Francisco Chronicle. ‘‘We didn’t, but I could kick myself now.’’
Starting in 1965, she took a hiatus from performing to raise her two daughters from her marriage to Prima.
She saw her profile buoyed in the 1980s and 1990s when rock stars plumbed some of the old Prima material. David Lee Roth remade their recording of ‘‘Just a Gigolo/I Ain’t Got Nobody,’’ and Brian Setzer had a hit with ‘‘Jump, Jive an’ Wail”; the original was also revived for a popular television ad for Gap.