There is no doubt that TV presenter Holly Willoughby is a social media star.
She has more than 4 million followers on Instagram, where she regularly posts pictures of her outfits. Brands lucky enough to be featured can expect a surge in sales.
Her influence was cemented this year when she was selected as an ambassador for Marks & Spencer. Edits of her favourite pieces from the retailer were released in September and October, and will continue throughout next year.