With almost a million combined Twitter and Instagram followers tracking her every hairstyle change and fashion purchase, Louise Roe is the definition of a modern-day style celebrity. But the television host (BBC and E!) who began her career as a magazine editor in the UK, hasn't let the social media fame go to her head. She's down-to-earth, ambitious and cool -- and, of course, incredibly well-dressed.

Though Jessica Alba may be one of the most beautiful faces in Hollywood, it's not her looks that got her to where she is today. At the age of 34, the Golden Globe-nominated actress, celebrated mother of two and savvy entrepreneur has built a multi-million-dollar fortune creating safe and nontoxic products for moms that are also stylish and functional. Now she's taking that same business acumen and attention to detail and expanding into the beauty market.

Olivia Palermo is the ultimate tastemaker. You can't scroll through Pinterest without seeing (and subsequently pinning) her sartorial brilliance. And more than one of our past "Tastemaker" subjects has cited Palermo as a style icon.

As the creator of Cupcakes and Cashmere, Emily Schuman is the Beyoncé of bloggers. Everything she does -- from party planning to recipe creation -- is executed to Pinterest perfection. And everything she touches turns to Internet gold.

To say Lucy Hale has a huge following for her role as the eccentric -- yet relatable -- Aria Montgomery on "Pretty Little Liars" would be a massive understatement. Millions of fans tune into the mystery every week, and along the way, Aria's over-the-top outfits, hair and makeup have achieved their own cult status.