Best Celebrity Makeovers of the Year

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Best Style Evolution: Sofia Vergara

"Believe me, I can look very cheesy," says the Modern Family star, 39, who now focuses on showing off only one asset at a time (think just cleavage or legs) in body-hugging styles by Vera Wang and Marchesa.

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Best Cleanup Act: Miley Cyrus

That nose piercing? Gone. Undershirts? History. The singer, 19, pairs chic deisgners like David Koma and Emilio Pucci with refined makeup (Nars Orgasm blush and DiorShow mascara are staples). "Even on days off, Miley wans to talk all things glam," her makeup artist Kevin Posey tells Us.

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Best Red Carpet Transformation: Stacy Keibler

"Over time, you learn simple things look better," the Fixing Pete star, 32, who traded trends for "timeless pieces" by designers Marchesa and Michael Kors, tells Us. Her makeup mantra: "Soft and classic," says pro Marina Gravani, who uses neutral colors by Laura Mercier and MAC.

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Best Hair Overhaul: Adele

"I have so much hair -- it's so big!" the Grammy winner, 23, has admitted. In February she went from reddish brown to a complexion-brightening honey hue and snipped it into a cool '60s-inspired flip.

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Best New Mom Crop: Ali Larter

One month after her son Teddy was born, the Resident Evil: Afterlife star, 36, chopped off several inches into a shaggy bob -- then went shorter a few weeks later. To keep it frizz-free, the organic-product devotee admits, "I sleep with conditioner on a few times a week."

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Best 5-Year Improvement: Taylor Swift

Three years ago, Swift told Us her favorite dress "is one that can be paired with cowboy boots." Now the singer, 22, prefers gowns by Reem Acra and Elie Saab, with Christian Louboutin pumps -- a style she calls "feminine, girlie." As for those natural waves, she tames them with a curling iron.

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Best 10-Year Improvement: Michelle Williams

"When you hit your thirties, you feel more in possession of your sexuality," says the My Week With Marilyn star, 31, who favors alluring 1930-era dresses. She also loves "vintage Victorian jewels," her stylist Kate Young tells Us. Her ultimate confidence booster? The platinum pixie cut, Williams says: "I feel like myself."

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Best 15-Year Improvement: Charlize Theron

Credit Dior. Since signing on as spokesmodel in 2004, the Snow White and the Huntsman star, 36, "has acquired a great eye" for flattering silhouettes, says her stylist Leslie Fremar. Overlooking trends for fitted cuts from Stella McCartney and Lanvin, Theron "likes low-cut necklines," says Fremar. "They make her look tall and thin."

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Best Teen-to-Twenties Transition: Shailene Woodley

The Secret Life of the American Teenager star, 20, "had crazy bangs that weren't right for her heart-shaped face," says stylist Patricia Vecchio. With the new style, "I don't use any products -- I just let it air-dry," Woodley tells Us. Her approach to fashion is equally low-key: "I buy all my clothes at thrift stores."

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Best Makeunder: Julianne Hough

The 23-year-old ditched her 6-inch extensions and perma spray tan. Growing out her eyebrows for June's Rock of Ages helped cement her au naturel update, brow guru Anastasia tells Us: "She looks sophisticated yet down-to-earth."

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Best Wig-Out: Rihanna

The singer, 24, rocked 12 weave styles in 2011! "She chooses looks based on her mood," stylist Ursula Stephen, who texts ideas back and forth with the beauty, tells Us. "The blonde is her favorite."