Brie Larson wins Best Actress Oscar for her role in Lenny Abrahamson's Room

The American actress landed the only win for the film, which had been nominated in four categories including Best Picture, Directing, and Adapted Screenplay.

Larson (26) has been acting since childhood and her performance in Room had already earned her several other gongs including the Golden Globe for Best Actress in a Motion Picture drama.

She paid tribute to Irish director Lenny Abrahamson and screenwriter Emma Donogue, who had both been nominated in their respective categories.

She also thanked her "partner through this", her nine-year-old co-star Jacob Tremblay and her real life partner Alex Greenwald.

“Thank you to the moviegoers. Thank you for going to the theaters and seeing our films," she concluded.

Meanwhile, Leonardo DiCaprio (41) finally won for his role in The Revenant and was met by fierce applause by the audience and his fellow nominees, including a beaming Michael Fassbender.

DiCaprio had previously been nominated five times but triumphed with his portrayal of real-life fur trapper Hugh Glass in Alejandro Gonzalez Inarritu's survival thriller, and he paid tribute to his collaborators as he stepped up onstage.

"Thank you all so very much...," Leonardo said. "To my brother in this endeavour, (co-star) Tom Hardy. Tom, your fierce talent onscreen can only be surpassed by your friendship offscreen.

"To Mr. Alejandro Inarritu, as the history of cinema unfolds, you have forged your way into history in these past two years; what an unbelievable talent you are..."

The winners

Best Picture: Spotlight

Best Actor: Leonardo DiCaprio, The Revenant

Best Actress: Brie Larson, Room

Best Director: Alejandro González Iñárritu, The Revenant

Best Supporting Actress: Alicia Vikander, The Danish Girl

Best Supporting Actor: Bridge of Spies

Best Original Screenplay: Spotlight

Best Adapted Screenplay: The Big Short

Best Costume Design: Mad Max: Fury Road

Best Production Design: Mad Max: Fury Road

Best Animated Film: Inside Out

Best Animated Short Film: Bear Story

Best Original Song: Sam Smith, Writing's On The Wall

Best Visual Effects: Ex Machina

Best Cinematography: Emmanuel Lubezki, The Revenant

Best Makeup and Hairstyling: Mad Max: Fury Road

Best Costume Design: Jenny Beavan, Mad Max: Fury Road

Best Live Action Short Film: Stutterer

Best Foreign Language Film: Son of Saul

Best Original Film Score: Ennio Morricone, The Hateful Eight

Academy Honorary Awards: Spike Lee, Gena Rowlands

Jean Hersholt Humanitarian Award: Debbie Reynolds.