LOS ANGELES (AP) _ Actress-singer Marion Colby, a popular nightclub personality and Broadway and television performer for more than two decades, has died at the age of 65, a former publicist said.

Miss Colby, who portrayed Milton Berle's wife in guest episodes of ''The Lucy Show'' starring Lucille Ball, died Thursday in a Los Angeles hospital following a lengthy illness, said publicist Irwin Zucker.

Miss Colby replaced Janis Paige on Broadway in ''Pajama Game'' in the 1950s and appeared on television in ''Broadway Open House,'' the ''Doodles Weaver Show'' and ''The Henny and Rocky Show,'' featuring Henny Youngman and Rocky Graziano.

Berle delivered the eulogy Sunday at Mt. Sinai Memorial Park.

Miss Colby is survived by her son, Robert, and a brother.