The Nebelung is a pedigree breed of domestic cat. Nebelungs have long bodies, wide-set green eyes, long and dense fur, and mild dispositions. The cat is related to the Russian Blue, but with longer, silkier hair, and is in fact sometimes called the Long-haired Russian Blue.

The Russian Blue cat, commonly referred to as just Russian Blue, is a cat breed with colors that vary from a light shimmering silver to a darker, slate grey. The short, dense coat, which stands out from the body, has been the breed's hallmark for more than a century.