According to a Harvey Nichols spokeswoman, the quote is inspired by Pretty Woman:
We developed the campaign to promote our summer sale and capture the excitement in a light-hearted, humorous way.
The images in our advertising were designed to be a visual representation of a well-known phrase.
During the production of the campaign, we researched the use of this expression in popular culture and social media and were satisfied that is is both commonplace and invariably used in a playful, inoffensive manner, which was in-keeping with the tongue-in-cheek spirit in which we intended our campaign to be taken. (source: nymag.com)