A monochrome and minimalist production of Sunset Boulevard has swept the board at the WhatsOnStage Awards.
Its star Nicole Scherzinger was named best performer in a musical, while Jamie Lloyd won best direction.
The show also won a string of technical prizes including best sound, video and lighting design.
A Little Life was the big winner in the play categories, scoring acting prizes for its stars James Norton and Luke Thompson.
The stage adaptation of Hanya Yanagihara's much-adored novel received mixed reviews and made headlines for its unflinching depiction of rape and self-harm.
But the four-hour show was extended after high ticket sales, with Happy Valley star Norton and Bridgerton's Thompson both praised for their performances.
Sunset Boulevard was praised by critics and made headlines for the number of standing ovations it received. Former Pussycat Dolls singer Scherzinger will star in the production once again when it opens on Broadway later this year.
The show won seven of the nine prizes it was nominated for, but it was beaten in the best musical revival category by the Bridge Theatre's Guys & Dolls.
In a statement, Darius Thompson and Alex Wood of WhatsOnStage said: "What a year for UK theatre this has been.
"It is striking just how audiences are keen to lend their support to bold, experimental takes on classic tales - from solo versions of Chekhov to immersive takes on classic musicals, or radical re-imaginings of Andrew Lloyd Webber shows."
Stranger Things: The First Shadow, the stage adaptation of the Netflix series, won best new play; while Vanya, a one-man performance of the Chekhov play starring Andrew Scott, was named best play revival.
Sex Education star Aimee Lou Wood won best takeover performance for Cabaret, a role that has also been played in the West End by Jessie Buckley and Amy Lennox and will soon be inhabited by Cara Delevingne.
The WhatsOnStage Awards, where the winners are voted by the public, have run annually since 2008, introducing gender-neutral categories for the first time last year, replacing the traditional best actor and best actress prizes.
This year's ceremony was held at the London Palladium on Sunday, hosted by Bonnie Langford and Melanie La Barrie.
The winners in full:
Best performer in a musical - Nicole Scherzinger, Sunset Boulevard, Savoy Theatre
Best supporting performer in a musical - Jack Wolfe, Next to Normal, Donmar Warehouse
Best performer in a play - James Norton, A Little Life, Harold Pinter Theatre and Savoy Theatre
Best supporting performer in a play - Luke Thompson, A Little Life
Best takeover performance - Aimee Lou Wood, Cabaret, The Kit Kat Club at the Playhouse Theatre
Best professional debut performance - Grace Hodgett Young, Sunset Boulevard
Best new musical - Operation Mincemeat, SpitLip, Fortune Theatre
Best musical revival - Guys & Dolls, Bridge Theatre
Best new play - Stranger Things: The First Shadow by Kate Trefry, Jack Thorne and the Duffer Brothers, Phoenix Theatre
Best play revival - Vanya, Duke of York's Theatre
Best West End show - Cabaret
Best regional production - The Lord of the Rings, The Watermill Theatre, Newbury
Best off-West End production - Love Never Dies in Concert, Theatre Royal Drury Lane
Best direction - Jamie Lloyd, Sunset Boulevard
Best musical direction/supervision - Alan Williams, Sunset Boulevard
Best casting direction - Jill Green, The Little Big Things, @sohoplace
Best choreography - Matt Cole, Disney's Newsies, Troubadour Wembley Park Theatre
Best costume design - Ryan Dawson Laight, La Cage aux Folles, Regent's Park Open Air Theatre
Best lighting design - Jack Knowles, Sunset Boulevard
Best set design - Bunny Christie, Guys & Dolls
Best sound design - Adam Fisher, Sunset Boulevard
Best video design - Nathan Amzi and Joe Ransom, Sunset Boulevard
Best graphic design - Muse Creative, Guys & Dolls