Ellen Albertini Dow

Ellen Rose Albertini Dow (November 16, 1913 – May 4, 2015) was an American film and television character actress and drama coach. She portrayed feisty old ladies and may be best known as the rapping grandmother Rosie in The Wedding Singer (1998), performing "Rappers Delight". Dow's other film roles include elderly lady Mary Cleary who "outs" her grandson in Wedding Crashers, Disco Dottie in 54, the recipient of Christopher Lloyd's character's slapstick in Radioland Murders and a choir nun in Sister Act.

She was best known to small screen audiences for her guest appearances on sitcom The Golden Girls. Description above from the Wikipedia article Ellen Albertini Dow,licensed under CC-BY-SA, full list of contributors on Wikipedia.