Where did Marie Osmound get the little black dress in nutri system commercial?

Marie Osmond's little black dress in the Nutrisystem commercial is not specifically noted for its origin in public sources. However, many celebrities often wear designer outfits or pieces from popular fashion retailers for promotional appearances. It’s likely that the dress was chosen for its stylish appeal to enhance her image in the advertisement. For exact details, one would need to check with fashion publications or interviews where she might discuss her outfit choices.