Cyrus, 20, copied Kim's look from the 1999 Video Music Awards, when the New York City rapper wore a one-sleeved mermaid-inspired jumpsuit and a purple wig, reported the Huffington Post.
The 'Wrecking Ball' hitmaker posted photos of her costume to photo-sharing website Instagram with the caption, "Happy Halloween."
In one photograph, she wrote, "Miley doing Lil Kim doing Miley."
Kim also liked her look and wrote, "Aww.