Since the Oscars are all about the dresses and suits (in our books, anyway), we can think of no better way to kick off one of our favorite annual festivities than with a jam-packed night of high style bashes. And last night saw not one, but three of fashion's best brought together when Angelina Jolie  in Saint Laurent , Brad Pitt , and a Jonathan Cohen-clad Lupita Nyong'o joined forces for the 12 Years a Slave pre-Oscars event. Also keeping busy were Cate Blanchett , Anne Hathaway , and Taylor Swift , who all brought their A-games to last night's parties.
Earlier in the week, Bulgari 's Decades of Glamour event was hosted by an Altuzarra-clad Naomi Watts  and attended by her chic set of friends, who included Kate Hudson  and Olivia Munn. While the jeweler looked to Old Hollywood, Vanity Fair had its eye on the future with a young Hollywood guest list that boasted Kiernan Shipka, Jena Malone, and Zoey Deutch. A look at the most stylish stars who've attended Oscars preparties, below.
Anne Hathaway at Chanel's Pre-Oscars Dinner
At the Chanel  bash, Anne showed a hint of skin with her sheer lace panel.
Sienna Miller at Chanel's Pre-Oscars Dinner
Sienna brought her signature cool to Chanel 's cocktail party.
Rosie Huntington-Whiteley at Chanel's Pre-Oscars Dinner
The model smoldered in her sheer black design while hitting the carpet for Chanel .
Greta Gerwig at Chanel's Pre-Oscars Dinner
Greta added a sweet accent to her Chanel  look with bowed heels.
Naomie Harris at Chanel's Pre-Oscars Dinner
Pretty in pink? Naomie sure was!
Lily Collins at Chanel's Pre-Oscars Dinner
Lily looked ladylike in a pretty, embellished skirt.
Poppy Delevingne at Chanel's Pre-Oscars Dinner
A bright blue bag added a fun burst of color to Poppy's pencil skirt.
Emilia Clarke at Chanel's Pre-Oscars Dinner
Emilia lightened up the night with a white look.
Angelina Jolie, Brad Pitt, and Lupita Nyong'o at Grey Goose Presents 12 Years a Slave
The 12 Years a Slave team joined forces for a stylish pre-Oscars appearance in head-to-toe black (Angelina wore Saint Laurent) and Lupita's Jonathan Cohen pop of color.
Cate Blanchett at Sony Pictures Classics' Oscars Dinner
Cate took a break from dresses and gowns in an asymmetric Stella McCartney  jumpsuit.
Taylor Swift and Jaime King at The Weinstein Company's Academy Awards Party
Taylor Swift  (in Oscar de la Renta) teamed up on the carpet with a smoldering Jaime King, who wore Ulyana Sergeenko's silk cocktail dress.
Oprah Winfrey at The Weinstein Company's Academy Awards Party
Oprah made an entrance in her sleek black column gown.
Anne Vyalitsyna at The Weinstein Company's Academy Awards Party
Anne brought her supermodel style to the carpet with a plumed cocktail dress.
Karlie Kloss at The Weinstein Company's Academy Awards Party
Karlie was red hot in Marchesa .
Lupita Nyong'o at the Women in Film Pre-Oscars Cocktail Party
Lupita Nyong'o accented her strapless (and striped) Michael Kors  dress, which featured a sexy cutout, with a pair of blue satin pumps.
Cate Blanchett at Giorgio Armani Celebrates Martin Scorsese and Paolo Sorrentino
Cate Blanchett  did the label proud in her sparkling Armani Privé dress.
Emmy Rossum and Dianna Agron at Giorgio Armani Celebrates Martin Scorsese and Paolo Sorrentino
The two red hot ladies made for stylish partygoers at the Armani bash.
Olivia Munn at Giorgio Armani Celebrates Martin Scorsese and Paolo Sorrentino
This caped crusader looked tough and elegant at once in her Armani look.
Naomie Harris at Giorgio Armani Celebrates Martin Scorsese and Paolo Sorrentino
Naomie Harris showed a hint of skin in her Giorgio Armani  designs.
Anna Kendrick and Aubrey Plaza at Giorgio Armani Celebrates Martin Scorsese and Paolo Sorrentino
Anna Kendrick  and Aubrey Plaza buddied up in steely looks at the Armani party.
Caitlin Fitzgerald at Giorgio Armani Celebrates Martin Scorsese and Paolo Sorrentino
Caitlin Fitzgerald gave pants a go while attending the Armani party.
Rachel Zoe at Giorgio Armani Celebrates Martin Scorsese and Paolo Sorrentino
Rachel Zoe  worked head-to-toe black while feting the nominees.
Jaime King at the Women In Film Pre-Oscars Cocktail Party
Jaime King showed some leg in Dior on the black carpet.
Helen Mirren at the Women in Film Pre-Oscar Cocktail Party
Helen added extra appeal to her Max Mara  shift with a statement necklace.
Lake Bell at the Women In Film Pre-Oscar Cocktail Party
Forget gold! Lake was a silver fox in her Max Mara  design while feting the Oscars.
Anna Kendrick at Vanity Fair's DJ Night
Anna sweetened things up in a floral Tory Burch  dress.
Zoë Kravitz at Vanity Fair Campaign Hollywood's DJ Night
Zoë Kravitz looked fresh in her green silk Calvin Klein  maxidress.
Kate Mara at QVC's Red Carpet Style Event
Kate Mara shimmered in her silver-embellished shift, Kurt Geiger  heels, and Jenny Packham  clutch.
Krysten Ritter at QVC's Annual Red Carpet Style Event
Krysten Ritter got in the trenches with a belted coat that she paired with her Rodo clutch and Kurt Geiger  heels.
Jared Leto at Los Angeles Confidential's Oscars Bash
Jared Leto  was the man of the hour at his Los Angeles Confidential party.
Diane Kruger at the National Hispanic Media Coalition Impact Awards
Diane Kruger  was sheer perfection in her cool white design.
Cate Blanchett at Catherine Martin's Rodeo Drive Walk of Fame Induction
Cate Blanchett  looked every inch a winner in her fringed column.
Kiernan Shipka at Catherine Martin's Rodeo Drive Walk of Fame Induction
Kiernan Shipka looked as adorable as ever in her retro ensemble.
Anne V. at Catherine Martin's Rodeo Drive Walk of Fame Induction
Anne V. surprised us with a pop of marigold on the black carpet.
Jessica White at Catherine Martin's Rodeo Drive Walk of Fame Induction
Those were some boots Jessica White wore!
Georgina Chapman at Catherine Martin's Rodeo Drive Walk of Fame Induction
Georgina Chapman gave us something pretty to look at while attending the Rodeo Drive event.
Kate Beckinsale at the Hollywood Domino and Bovet 1822 Gala
Kate kept Dior's strong red carpet season going in the label's black-and-blue cocktail dress.
Vanessa Hudgens at the Hollywood Domino and Bovet 1822 Gala
Jenny Packham 's scarlet gown was a bold choice for Vanessa Hudgens .
Jon Hamm at the Hollywood Domino and Bovet 1822 Gala
Not letting the ladies get all the attention, Jon Hamm  caught our eye in a dapper plaid suit.
Maria Bello at the Hollywood Domino and Bovet 1822 Gala
Even though Maria Bello matched the black carpet, she certainly didn't blend in, wearing a fringe design.
Dave and Odette Annable at the Hollywood Domino and Bovet 1822 Gala
The couple continued their chic week in prints, including snakeskin and polka dots.
Amy Adams at Vanity Fair's American Hustle Toast
Amy Adams  couldn't be missed in her off-the-shoulder Vivienne Westwood  number.
Naomie Harris at Suzy's Global Sustainable Design Campaign Cocktail Party
Naomie Harris heated things up in a sleek Altuzarra  LBD and bright heels.
Amber Valletta at Suzy's Global Sustainable Design Campaign Cocktail Party
The model showed us another side in her backless black gown.
Lupita Nyong'o at LoveGold Celebrates Lupita Nyong'o
Lupita arrived for her pre-Oscars party in a bright blue ensemble that she paired with Elena Votsi jewels.
Naomie Harris at LoveGold Celebrates Lupita Nyong'o
Naomie opted for an evening-ready jumpsuit at Sally Morrison and LoveGold's celebration for Lupita Nyong'o.
Jessica Szohr at LoveGold Celebrates Lupita Nyong'o
Jessica Szohr  also opted for black pants at the LoveGold bash.
Bella Thorne at LoveGold Celebrates Lupita Nyong'o
Bella Thorne gave her back to the camera for good reason in a House of Ronald dress.
Gillian Jacobs at LoveGold Celebrates Lupita Nyong'o
Gillian Jacobs let her pendant necklace do the talking by pairing it with a sleek black design.
Ashley Greene at Global Green USA's Annual Oscar Party
Ashley Greene  went pink at Global Green USA's annual Oscar party.
Malin Akerman at Global Green USA's Annual Oscar Party
Malin Akerman refreshed us with Wes Gordon 's pastel dress.
Maggie Grace at Global Green USA's Annual Oscar Party.
Maggie Grace channeled Old Hollywood glamour in a silky cocktail dress.
Naomi Watts at the Bulgari Decades of Glamour Oscar Party
Altuzarra 's neon-accented sheath highlighted the curves of the evening's hostess and let her Bulgari  necklace shine.
Emmy Rossum at the Bulgari Decades of Glamour Oscar Party
J. Mendel's asymmetrical silk dress was a smoldering choice for the Shameless star.
Ashley Greene at the Bulgari Decades of Glamour Oscar Party
Ashley slinked into the bash in a sexy Dsquared2  LBD and Casadei  stilettos to match.
Olivia Munn at the Bulgari Decades of Glamour Oscar Party
Cool metallics looked particularly hot when Olivia Munn arrived in Bibhu Mohapatra's strapless cocktail dress and Casadei 's satin pumps.
Kate Hudson at the Bulgari Decades of Glamour Oscar Party
Kate looked like a breath of fresh air in a plunging yellow Pucci  blouse that she set off with summery white accents.
Dianna Agron at the Bulgari Decades of Glamour Oscar Party
The actress stuck to the black palette with her coordinated ensemble.
Camilla Belle at the Bulgari Decades of Glamour Oscar Party
An off-the-shoulder white design was a dramatic choice for Camilla.
Nick Jonas at the Bulgari Decades of Glamour Oscar Party
Nick Jonas  was one stylish guy in Sandro 's separates.
Jordana Brewster at the Bulgari Decades of Glamour Oscar Party
Jordana bared her midriff in Pamella Roland 's sleek separates.
Erin Wasson at the Bulgari Decades of Glamour Oscar Party
Erin demonstrated her supermodel style in a curve-hugging burgundy design.
Kiernan Shipka at the Vanity Fair Young Hollywood Party
We loved Kiernan's shoes (and her yellow heels weren't half bad either!).
Kate Mara at the Vanity Fair Young Hollywood Party
Kate looked as lovely as ever in her Dior design.
Zoë Kravitz at the Vanity Fair Young Hollywood Party
Zoë took the plunge in a silk draped-neck Calvin Klein  Collection dress.
Dave and Odette Annable at the Vanity Fair Young Hollywood Party
The couple coordinated flawlessly in shades of gray.
Jena Malone at the Vanity Fair Young Hollywood Party
The always stylish star dared to wear a fashion-forward Roksanda  Ilincic jumpsuit.
Cobie Smulders at the Vanity Fair Young Hollywood Party
The How I Met Your Mother star showed some leg with a surprising hem.
Stacy Keibler at the Vanity Fair Young Hollywood Party
Stacy brightened up the room in a hot-pink Joseph suit that she paired with Jimmy Choo  heels and Jennifer Fisher  jewels.
Bella Thorne at the Vanity Fair Young Hollywood Party
Bella also suited up, while opting for a metallic short ensemble.
Jaimie Alexander at the Vanity Fair Young Hollywood Party
Even though she wasn't showing skin, Jaimie looked sexy in a colorful print dress and animal-print Aperlai sandals.
Zoey Deutch at the Vanity Fair Young Hollywood Party
Zoey sweetened things up in Dior.