Lady Gaga's white dress was more pedestrian than her usual getups, but she still stood out from the crowd looking totally ethereal. (Photo by Josiah Kamau/BuzzFoto via Getty Images)
Sienna Miller, 32, looked killer in an updated version of an old-Hollywood glam cocktail frock. The super chic look consisted of a retro Bardot neckline, sheer sleeves and beaded tassels. (Photo by NCP/Star Max/GC Images)
Fashionista Kate Bosworth looked casual-chic looking polished with a boho-flair. The actress, 31, wore cropped black slacks with a printed sweater and black brogues. (Photo by Frazer Harrison/WireImage)
Emily Blunt, 31, kept it casual in printed pants, sweater and espadrilles. A blue messenger bag completed her look. (Photo by RB/Bauer-Griffin/GC Images)
Model Irina Shayk, 28, bundled up in a huge fur hood and knee-high boots. (Photo by Raymond Hall/GC Images)
Swoon! Orlando Bloom, 37, looked fantastic in gray pants and a cool black jacket. Leather sneakers completed the hunk's look. (Photo by GVK/Bauer-Griffin/GC Images)
Young actress Chloe Moretz,17, looked her age at the airport in jeans, sneakers and a striped tee. Edgy sunglasses added a touch of flare. (Photo by GVK/Bauer-Griffin/GC Images)
Krysten Ritter, 33, looked better than ever in a super chic coat and to-die-for heels.(Photo by Ray Tamarra/GC Images)
Model Suki Waterhouse, 22, was the ultimate cool girl as she walked her adorable dog in NYC. We love her belted coat, combat boots and beanie. (Photo by Raymond Hall/GC Images)
Bradley Cooper, 39, sure cleans up well! The hunky Hollywood star-turned-Broadway actor looked dapper in a fitted suit and perfect coif. (Photo by Rob Kim/Getty Images)
Cameron Diaz, 42, was a total sexpot in a simple sweater dress and heels. Messy hair and a sultry pout completed her look. (Photo by Neil Mockford/Alex Huckle/GC Images)
Krysten Ritter, 33, killed it again in a midi-length metallic skirt, bustier top and chic coat. (Photo by GWR/Star Max/GC Images)
Amy Adams, 40, stunned in a floor-length belted shirtdress that complemented her fiery locks. (Photo by Patricia Schlein/Star Max/GC Images)
We love a long coat on a man! Zachary Quinto, 37, looked fabulous for just walking his dogs in a red coat, knit cap and scarf. (Photo by Josiah Kamau/BuzzFoto/FilmMagic)
Model Poppy Delevingne, 28, was downtown chic in leather skinnies and fun accessories. (Photo by Neil P. Mockford/Getty Images for Coccinelle)
Taylor Swift, 25, was a total cutie in a plaid coat, purple knit cap and matching maroon accessories. (Photo by Ignat/Bauer-Griffin/GC Images)
Nick Jonas, 22, is having (another) moment. The "Jealous" singer was smokin' in distressed jeans, tailored coat and fun fedora. (Photo by Josiah Kamau/BuzzFoto via Getty Images)
Reese Witherspoon, 38, was very put-together and proper in a preppy daytime look. (Photo by Bauer-Griffin/GC Images)
Say cheese! Emma Stone, 26, was all smiles in an all-black outfit. The only thing that makes us cringe is her bare legs in the cold NYC weather. (Photo by ESBP/Star Max/GC Images)
With cameras flashing around them at all times, celebs best be ready for a photo op at any moment.
Lady Gaga is known for her eccentric fashion sense, but the pop star-turned-jazz crooner toned it down in a relatively pedestrian outfit. The "Mother Monster," 28, channeled Marilyn Monroe in a slinky sheer white gown and platinum blonde hair.
Actress Sienna Miller, 32, also channeled old Hollywood glam in a very sexy white cocktail dress. The stunning sheer frock featured a retro Bardot neckline and beaded tassels.
Fashionista Kate Bosworth kept it casual in her usual tailored-boho look. The actress, 31, looked put-together in on-trend cropped-flared pants, printed sweater and black brogues.
Check out our picks for the week's sexy celeb style above.