Sheridan had celebrated her 93rd birthday earlier this week, Hendon said.

She is survived by her daughter and son-in-law. Though she had dozens of film credits,

she was best known as Seinfeld's doting mother on his titular sitcom,

which ran for nine seasons. She also appeared as the snoopy neighbor Mrs. Ochmonek on the alien-led sitcom "ALF."

A trained dancer, Sheridan made her Broadway debut in 1971 in "Frank Merriwell" and appeared in several more productions,

including the Meryl Streep-starring musical "Happy End" in 1977, until focusing primarily on film and TV from the 1980s onward.

Sheridan was an author, too, penning the autobiographical "Dizzy & Jimmy" about her relationship

with a young, pre-stardom James Dean when the two were aspiring Broadway performers.

At the time of her death, she'd been working to develop the book into a film, Hendon said.

Sheridan's death comes within two weeks of the death of fellow "Seinfeld" cast member Estelle Harris,

Liz Sheridan dead at 93