Hair's the Scoop

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Nicole Richie, Mary-Kate Olsen, and Emma Roberts model "undone" waves at an Elizabeth & James event in LA.

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Ashley models a classic, side-parted updo at Thursday's Metropolitan Opera gala, whilst Mary-Kate opts for a center-parted style.

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The stars were shining bright at this year's CFDA/Vogue Fashion Fund Awards, with Carey Mulligan winning my vote for Best(est) Tressed.

Aside from being ultra flattering, the "Never Let Me Go" lead's smooth, side-parted bob acts as the perfect complement to the bold neckline of her Chanel dress. (Don't you think?)

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Whilst both moguls model a smoked-out eye and porcelain complexion, Mary-Kate opts to differentiate herself with tousled waves and a berry lip, whereas Ashley rocks defined brows and a smooth, straight hairstyle.

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Full, fabulous brows like Ashley and Mary-Kate's are timeless, ageless and oh-so-sexy. Achieve a similar look with these tried & true essentials:

To Grow: Peter Thomas Roth Brows to Die For Eyebrow Conditioning Treatment
A daily eyebrow treatment with patent-pending technology helps enhance the appearance of sparse, uneven and over-plucked eyebrows. ($85, Nordstrom.com.)

To Groom: Japonesque
Ergonomic Mini Tweezer Set
Eliminating errant hairs with superior comfort and control, this brilliant set features both fine point and slant tip tweezers — allowing for professional precision every time. ($29, Beauty.com.)

To Fill: Anastasia Brow Ex-press
An all-inclusive kit containing multiple brow stencils, a duo of pigments in your range (blonde or brunette) to custom blend the most natural brow color, an angled brush for clean application, cream highlighter, and wax cream to help hold a perfect shape all day.
($38, Sephora.com.)

To Fake: Eyebrow Extensions
They're quick, natural-looking and can last up to 4 weeks. So where to go? I'm loyal to Completely Bare's "Barshop Brow" service but, if you can't get to one of their locations, seek a salon or spa that offers brow grooming and/or lash extension services. They'll likely have something similar on their menu, or know of who might.

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Mary-Kate Olsen shimmers in a burnished bronze eye at the NY premiere of "Holy Rollers."

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Fergie and Mary-Kate Olsen each debuted a new, eye-catching look this week— though their choice of color and style couldn't be more different.

Pictured here at the 34th Annual March Of Dimes Beauty Ball, Fergie appears to have darkened her (normally blonde) tresses and opted for a pin-straight style. It's a more refined, sophisticated look for the songstress, and one that I adore.

Mary-Kate, on the other hand, chose to lighten her locks for last night's Anniversary Gala at the Metropolitan Opera. It may not be an everyday look, but I'm loving her tousled texture and dramatic side part. It's youthful, and adds an edge to her elegant ensemble.

All in all, two very different but equally appealing styles, in my opinion.