EXCLUSIVE: Inside Oscars After-Parties: Warren Beatty Keeps the Envelope!

ET was at the most star-studded parties following Hollywood's biggest night.

After an eventful 89th Academy Awards, the stars were ready to put the flubs behind them and celebrate Hollywood's big winners of the night.

ET's insiders were at all the exclusive after-parties on Sunday night, and got a glimpse at how the stars let loose! From Elton John's annual Oscars bash to the star-studded Governors Ball to Vanity Fair's invite-only soiree, check out what went down once the Academy Awards ended and the real partying began:

MORE: 9 Things You Didn't See On-Air at Oscars -- Cocktails, Chaos and Chefs


89th Annual Academy Awards Governors Ball

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After the epic Best Picture snafu at the end of the Oscars, presenter Warren Beatty and Faye Dunaway were ready to let off some steam. At the Hollywood & Highland Center, Beatty was seen still holding an Oscars envelope after he and Dunaway accidentally read off La La Land as Best Picture when Moonlight was actually the winner.

An ET insider also spotted La La Land star Emma Stone at the after-party, and noted that she was racing through the ball to get her Oscar engraved.

Viola Davis was celebrating her Oscars win and looking out for a pal of hers at the same time. Grabbing a glass of champagne, the Fences star was seen walking with husband Julius Tennon to get her award engraved, but turned around when she noticed that her friend was denied access to the area. Davis came to her rescue and her friend was eventually allowed entry into the VIP spot.

Empire star Terrence Howard arrived with Mira Pak to the party, but when asked if he'd like to talk with reporters, the 47-year-old actor quipped, "Had a little too many."

Also spotted at the soiree was Priyanka Chopra, Octavia Spencer, Samuel L. Jackson, Nicole Kidman and husband Keith Urban, Vince Vaughn and wife Kyla Weber, Pharrell Williams and producing partner Mimi Valdes, LaLa Land producer Jordan Horowitz, Oscar winner Mahershala Ali, Loving's Ruth Negga and CBS President and CEO Leslie Moonves and wife Julie Chen.


WATCH: Emma Stone Reacts to Oscars' La La Land Best Picture Screw-Up -- 'I F**king Love Moonlight'


25th Annual Elton John AIDS Foundation's Academy Awards Viewing Party

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ET's eyewitness said Elton John was in good spirits during his party at the City of West Hollywood Park on Sunday night, which included guests Caitlyn Jenner, Colton Haynes, Ashley Tisdale, Kathy Hilton, Katharine McPhee, Garrett Clayton and Aisha Tyler.

This Is Us stars Chrissy Metz and Justin Hartley were also at the annual bash, with Metz bringing boyfriend Josh Stancil as her date. The 36-year-old actress was spotted politely chatting with a fan upon entering the party's press line, and was later seen snapping a photo with another admirer of hers.

As for Hartley, he was seen happily chatting with a group of fans.

Other stars spotted mingling included Girls actor Andrew Rannells, who greeted Glee's Kevin McHale with a hug.

Meanwhile, Fuller House star Candace Cameron Bure was seen dancing at the bash.


WATCH: How the Oscars Best Picture Mix-Up Happened -- Everything We Know About the Envelopes So Far!


2017 Vanity Fair Oscar Party hosted by Graydon Carter

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All the A-listers hit up this after-party, including frenemies Matt Damon and Oscars host Jimmy Kimmel.

Katy Perry was joined by boyfriend Orlando Bloom and bestie Allison Williams at the event, but she wasn't the only one mingling with her famous friends at the exclusive after-party. Mindy Kaling brought her former Office co-star and pal, BJ Novak, as her date, and also hung out with her Reese Witherspoon, who she just wrapped filming with on the movie A Wrinkle In Time.

Mindy Kaling brought her former Office co-star and pal, BJ Novak, as her date, and also hung out with her Reese Witherspoon, who she just wrapped filming with on the movie A Wrinkle In Time.

Pascal Le Segretain/Getty Images

It was quite the date night for many celebrities at the after-party. Justin Timberlake and wife Jessica Biel, hit up the event, as well as Nick Offerman and Megan Mullally, Will Arnett and girlfriend Elizabeth Law, James Corden and wife Julia Carey, and Jeff Goldblum and his pregnant wife, Emilie Livingston.

Mariah Carey, Kate Hudson and Gabrielle Union also hit the red carpet, and wowed in stunning party dresses.

Pascal Le Segretain/Getty Images


PHOTOS: The Best, Worst and Most Revealing Dresses at the Vanity Fair Oscars After-Party

In addition to hitting up all the exclusive after-parties, ET was also backstage at the Oscars and got a firsthand account of what goes down behind the scenes of such a big awards show. Check it out:

Additional reporting by Tracie De La Rosa, Brendon Geoffrion and Joseph Corral.
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