Julianne Moore (Gracie) did not notice Natalie Portman (Elizabeth) was improvising by mimicking her mannerisms in some scenes until later into filming.
Natalie Portman brought the script to Todd Haynes as a potential collaboration between the two. Haynes bit, as he loved the script, and then suggested Julianne Moore for the role opposite Portman.
D.W. Moffett, who played Gracie's ex-husband Tom, heads the film and television department in Savannah College of Art and Design. Students from the acting program participated in this film.
The title is an expression used to refer to a romantic relationship with a large age gap between a couple.