Attending "TimesTalks: A Final Farewell to HBO's Girls," the actress wore an adorable retro Fendi dress.
The star stunned in a sparkly Balmian gown at the 22nd Critics' Choice Awards.
The Get Out actress stood out at the Tony Awards, ditching a gown in favor of a plunging white pantsuit by DKNY.
The Girls actress stunned in a shimmering Peter Pilotto gown.
The actress opts for a golden yellow look at the QVC presents "FFANY Shoes on Sale" event at the Waldorf Astoria Hotel in New York City.
The actress is seen at the 2015 Fashion Group International Night Of Stars Gala at Cipriani Wall Street in New York City.
The actress attends the SAMA eyewear launch of deCODE:Los Angeles at Baccarat New York.
The actress attends the 2015 China: Through The Looking Glass Costume Institute Benefit Gala at the Metropolitan Museum of Art.
Ms. Williams works a darkly feminine Michael Kors number at the designer's eyewear collection event in NYC.
Alongside Michael Kors and Kate Hudson, the Girls star rocks a chic in a crop top ensemble at the designer's NYFW Fall 2015 show.
She hit up HBO's Post 2015 Golden Globe Awards after party in a delicate tiered Armani Privé gown.
Ms. Williams is ultra-romantic in a Monique Lhuillier design with a sparkling sheer skirt at the Girls premiere.
She flashes a sliver of midriff in a two-piece Vionnet combo at the 2014 Global Citizen Festival in NYC.
For the 2014 Emmys, the actress slips on a mesmerizing Giambattista Valli couture ball gown.
The starlet looks ready to walk down the aisle in a delicate lace Dolce & Gabbana number at the Museum of Moving Images event in NYC.
Glam alert! Allison captivates in a coral Oscar de la Renta gown with an exaggerated train at the 2014 Met Gala.
Don't be fooled; Allison's convservative Emilia Wickstead wool-crepe gown from Vanity Fair's Oscars Party 2014 actually has a playful plunging back.
At the Rag & Bone fashion show at NYFW spring 2015, Allison blends a cream top with an elegant pearly skirt.
At the Diane Von Furstenberg show, the actress styles a prim white frock with bold checkered detail.
All eyes on Allison! The actress turns more than a few heads at the Girls season three London premiere wearing a striking black Alexander McQueen gown with a vibrant jeweled neckline.
For the 2014 Golden Globes, she picks a striking Alexander McQueen design with a textured, striped bodice.
Allison again steals the show in a geometric David Koma design with mesh paneled detail at the 2014 People's Choice Awards.
She's a class act in a jeweled Christian Dior frock at the Girls season three premiere.
She selects a bold Oscar de la Renta number with an ultra-sheer lace bodice offset be a billowing tulle skirt at the Met's Winter Ball for Autism in NYC.