Congratulations to all the winners! Here's a complete rundown of what happened during the Oscars ceremony inside the Dolby theaters.
Best Picture- 'Birdman'
"Maybe next year there'll be some immigration rules to the Academy - two Mexicans in a row is suspicious," director Alejandro G Inarritu joked when he collected the best picture prize, referencing Alfonso Cuaron's best director win last year.
Michael Keaton paid tribute to Inarritu saying: "This has been a tremendous experience - this guy is as bold as bold can be. It's just great fun to be here."
Inarritu finished his speech saying: "I dedicate this award for my fellow Mexicans who live in Mexico. I pray we can find and build a government we deserve and I hope Mexican immigrants in this country can be treated with the same dignity as the ones who came before and built this immigrant nation."
Best Actress - Julianne Moore for 'Still Alice'
Crying, Julianne Moore "I read an article that said winning an Oscar could lead to living five years longer. If that's true, I want to thank the Academy, because my husband is younger than me!"
"To my husband Bart, thank you for my life, thank you for giving me a home."
Best Actor- Eddie Redmayne, 'The Theory of Everything'
Eddie Redmayne literally skipping and jumping on stage. "I don't think I'm capable of articulating how I feel - I am fully aware I am a lucky, lucky man.
"This Oscar belongs to all those people around the world battling ALS," he said. "It belongs to one exceptional family - Stephen, Jane and the Hawking children - and I will be its custodian and I will look after him; I'll polish him and wait on him hand and foot."
He paid tribute to his 'partner in crime' and co-star Felicity Jones, and his 'ferocious and kind director' James Marsh.
Best Director: Alejandro G Inarritu , 'Birdman'
He paid tribute to his fellow nominees, scorning ego and competition.
"For someone to win, someone has to lose - but true art, true individual expression cannot be compared. Our work, as always will be judged by time."
Best adapted screenplay - The Imitation Game, Graham Moore
"When I was 16 years old, I tried to kill myself. I felt weird and different and felt like I didn't belong. Now I'm standing here this is for any kid out there who doesn't feel like they belong, because you do," - Graham Moore
Best original screenplay - Birdman
Birdman director Alejandro G Inarritu thanked his fellow scriptwriters Nicolas Giacobone, Alexander Dinelaris, Jr and Armando Bo as he picked up the award for best original screenplay.
"Three years ago, I invited them to follow me in a crazy idea - and because they are crazy, they did it."
Best original score - The Grand Budapest Hotel, Alexandre Desplat
Stunning performances from John Legend, Common and Lady Gaga that lifted the Oscars 2015
Flawless Lady Gaga never looked and sang better. She deserves the title of 'Lady' at the Oscars.
Lady Gaga paid an exceptional tribute to Julie Andrews singing songs from 'The Sound of Music.'
Julie Andrews just walked on stage out of nowhere!!
"Dear Lady Gaga, thank you for that wonderful tribute" - Julie Andrews "It's hard to believe 50 years have gone by since that joyous film was released. I blinked and here I am."
Scarlett Johansson has introduced a tribute to The Sound of Music - which won five Oscars including best picture in 1966 - celebrating it's 50th anniversary.
Best original song - Glory, Selma
Common - "I would like to thank God that lives in us all. Recently John and I got to go to Selma and perform on the bridge that Dr. King marched on 50 years ago ... the spirit of this bridge was built on hope."
Legend - "Selma is now, because the struggle for justice is right now."
Idina Menzel and John Travolta are together on stage - a year after the latter famously stumbled on Menzel's name when introducing her perform Let It Go.
John Legend and Common take to the stage now to perform Glory from Selma.
Best Documentary Feature: Citizenfour
Best Film Editing: Whiplash, Tom Cross
Jennifer Hudson takes the stage to sing and honor all those died last year
Meryl Streep takes the stage. Things take a somber turn as they remember the ones whom they lost in 2014.
Meryl Streep - "Through their work, they shared a piece of their soul."
"There will never be anyone like them, each and every one."
Best cinematography - Emmanuel Lubezki for 'Birdman'
Second consecutive Oscar for Emmanuel Lubezki, who won the same award for 'Gravity' last year.
He said he wanted to share this honour with all the cast and crew, but particularly 'Birdman' director Alejandro G Inarritu "for your curiousity, your passion and your friendship".
Best production design - The Grand Budapest Hotel, Adam Stockhausen and Anna Pinnock
Animated Feature Film: Big Hero 6
Best animated short film - Feast - Patrick Osborne and Kristina Reed
Best visual effects - Interstellar, Paul J Franklin, Andrew Lockley, Ian Hunter, Scott R Fisher.
Time for another performance - representing the Brits, Rita Ora singing Grateful from Beyond the Lights.
Best supporting actress - Patricia Arquette, Boyhood
Patricia Arquette played a mom dealing with reality and difficulties raising kids by herself in 'Boyhood'.
Patricia with her daughter Harlow Olivia Calliope
In her winning speech Arquette paid tribute to "every woman who gave birth, paid their taxes... we have fought for everybody else's equal rights. It's our time to have wage equality"
And Meryl Streep's reaction to that point is priceless.
EU SOU A MERYL pic.twitter.com/trDeHuXkze— matheus (@whomath) February 23, 2015
"The host is wearing just shoes and underwear...
Neil Patrick does a parody of 'Birdman' scene where Michael Keaton had to walk in his underwear around back to the stage for his performance.
In a spoof of 'Birdman' and 'Whiplash', Neil is locked out of his dressing room and is forced to walk on stage in his underwear, while accompanied by 'Whiplash' star Miles Teller on the drums.
Best sound mixing - Whiplash, Craig Mann, Ben Wilkins and Thomas Curley
Best sound editing - American Sniper, Alan Robert Murray and Bub Asman
Gwyneth Paltrow honoring Glenn Cambpell and now Tim McGraw singing in his honor.
Tim McGraw performs a best original song nominee - I'm Not Gonna Miss You from Glen Campbell... I'll Be Me.
Best documentary short - Crisis Hotline: Veteran Press 1, Ellen Goosenberg Kent and Dana Perry
Best live action short film - The Phone Call, Mat Kirkby and James Lucas.
Live performance of 'Everything is Awesome', another nominee for best song. The stage is rocking with technicolour mechanics holding mini Lego Oscars.
Oscar has snubbed Lego from the nomination for best animated movie.
Best foreign film - Ida (Poland)
Ohh no - Ida director Pawel Pawlikowski's speech has been curtailed and be played the 'get off' music.
However Pawel didn't get down and thanked everyone he wanted to.
"This film is all about silence and contemplation and here we are at the epicenter of noise. Life is full of surprises," he said.
Best make-up and hair - The Grand Budapest Hotel.
Britons Frances Hannon and Mark Coulier took the Oscar for best make-up and hair for their work on The Grand Budapest Hotel.
Best costume design - The Grand Budapest Hotel
Jennifer Lopez and Chris Pine gave away the award for Best Costume Design to 'The Grand Budapest Hotel'.
Neil Patrick Harris has just revealed the Oscar goody bags contain $160,000 worth of merchandise including make-up, shoes and two holidays.
Audiences are treated to all the tracks nominated for best song throughout the ceremony. First up is Maroon 5's Adam Levine, performing Lost Stars from 'Begin Again'.
Whiplash star JK Simmons picked up the first Oscar of the night.
He paid tribute to his wife as "the most remarkable person I know" and his "above-average children" whom he called "extraordinary human beings". "And that's because you are a reflection of your mother," he joked.
Best supporting actor - JK Simmons, Whiplash
No surprise for the first prize of the night. People have been rooting for JK Simmons all the way to win this award.
The big moment is finally here.
After all the predictions, red-carpet avalanche, and lobbying after all the visits to the far-flung film festivals to gather all the votes it's time for the show.
Neil Patrick Harris's opening line: "Tonight we honour Hollywood's best and whitest - sorry brightest."
Well, he is trying to be funny and make people laugh before most of them starts losing.
First up - a Tony-style song and dance number with Neil Patrick Harris singing about bitter Oscars losers and a tribute to movies in all their glory.
Now Anna Kendrick on the action dressed in her Into the Wood's costume.
Jack Black sings his own ranty-song about film in great comedy fashion.
There really are no words -- this is easily one of the best musical numbers in Oscars history, so much diverse talent -- more Jack Black, more Kendrick.
Neil Patrick Harris has pointed out that this year's best film nominees collectively grossed one of the lowest ever totals.
Altogether, they grossed $600m - American Sniper was the most successful, accounting for more than $300m.