Stars of the stage gave messages of "faith and hope" at Sunday's Olivier Awards, as most theatres remain closed because of the pandemic.
Winners encouraged those working in the arts to stay positive about the future, and look ahead to a time when live performances will be able to resume.
Dear Evan Hansen and & Juliet were among the big winners, while Fleabag star Andrew Scott was named best actor.
He urged those in the industry to "keep the faith" as he accepted his trophy.
"I cant wait to be back on the boards and having a laugh again as soon as we can," he said.
The actor won for his performance in the Noel Coward play Present Laughter, and said he was "genuinely thrilled" to win an Olivier.
"A sense of humour that is incredibly important for us people in the theatre," he said. "It's something that's helped us all survive in the last few months during this incredibly arduous time."
'We must know our worth'
The Oliviers are the most prestigious awards event in UK theatre. Sunday's ceremony was hosted by Jason Manford at the London Palladium, and took place without an audience.
Shows which opened in the year to February 2020 were eligible for this year's prizes. The ceremony normally takes place in April, but it was delayed this year due to the pandemic.
Most theatres have remained closed since lockdown was imposed in March, but some venues have tried to re-open with social distancing restrictions in place.
Several of this year's winners praised the freelancers who work in the industry and looked ahead to a time when theatres would be allowed to fully reopen.
Sharon D Clarke, who was named best actress for her performance in Arthur Miller's Death of a Salesman, said theatre professionals must "know their worth".
"We must know what our incredible industry brings not only to the coffers, but to the soul of our nation," she said. "Keep the faith people, we will be back."
Perhaps the most poignant speech of the night came from Marianne Elliott, who jointly won best director with Miranda Cromwell for Death of a Salesman.
"This is a happy day and this is a sad day, because of what theatre was, and because none of us know when it will properly return," she said.
"Any shows that are happening right now are, let's make no bones about it, running at a loss. All our theatre practitioners are mainly freelancers and a lot of them have slipped through the cracks, and have not had any benefits since March.
"But it is a happy day because it reminds us of what theatre is, what it can do, and how it can touch hearts, minds and souls."
Miriam-Teak Lee, who won best actress in a musical for her leading role in & Juliet, referred to the unusual nature of this year's ceremony.
"Even though it's not the awards show as we know it, it doesn't make it any less special," she said.
The Duchess of Cornwall made an impassioned speech in support of theatre as she presented a special award to lyricist Don Black.
"Those of us who believe in the theatre also believe in its resilience," she said. "It is a cornerstone of a fertile cultural life, a forum for debate, and a powerful means of building community.
"After all, a play can be many things - funny, heartbreaking, cathartic, comforting. It can entertain us for an evening, or enrich the soul forever."
She added: "I should like to thank those of you whose profession is in the theatre for your determination and your flexibility. Please remain resilient - we need you and we have missed you."
Who won what?
Dear Evan Hansen, which debuted in London's West End last year after a hugely successful Broadway run, was named best new musical.
The show tells the story of a young boy with social anxiety, who, in an effort to become more popular, pretends he was close friends with a classmate who took his own life.
Its other prizes included best original score, as well as best actor in a musical for Sam Tutty, who plays the titular character.
The other musical acting categories were dominated by & Juliet, with Miriam-Teak Lee winning best leading actress, while her co-stars David Bedella and Cassidy Janson took home best supporting actor and actress.
The musical explores what would have happened to Juliet if she hadn't died along with Romeo at the end of Shakespeare's play.
The show features the music of songwriter Max Martin, who has written tracks for Britney Spears, Katy Perry, Pink, The Backstreet Boys and Ariana Grande.
In her speech, Janson said: "Thank you to every single person in & Juliet, you are the most glorious human beings to work with. You are so skilled, so valuable, don't any of you ever re-train."
Her comment was a reference to a recently-launched government scheme which is intended to encourage adults to consider new careers, as the economy changes due to the coronavirus pandemic.
Accepting his award for best supporting actor in a musical, Bedella added: "To everybody out there in the theatre community who is at times reaching a moment of despair lately: hold strong, we will be back in live theatres before we know it."
Sir Tom Stoppard's Leopoldstadt was named best new play, while Fiddler on the Roof won best musical revival and Cyrano De Bergerac best revival.
The latter show, which starred James McAvoy, was written by Edmond Rostand and originally performed in 1897.
Matthew Bourne won the ninth Olivier of his career thanks to his choreography on Mary Poppins, making him the individual with the most Olivier Awards.
Emilia took home three prizes including best costume and sound design, as well as one of the night's top awards - best new comedy.
The show is based 17th Century poet Emilia Bassano - who was known as the "dark lady of Shakespeare" as she was rumoured to be the playwright's muse.
Sir Ian McKellen was honoured with his seventh Olivier Award for the tour he embarked on to celebrate his 80th birthday.
"I didn't want to have a birthday party," Sir Ian told Manford. "I didn't think there was anything to celebrate.
"So, I thought if I go out of London no-one will be able to find me... I initially thought I'll go around the world... then when I counted up there were nearly 80 theatres that I knew and loved in this country so I thought why bother going abroad?"
The winners in full
Best new play - Leopoldstadt
Best new musical - Dear Evan Hansen
Best new comedy - Emilia
Best revival - Cyrano De Bergerac
Best musical revival - Fiddler On The Roof
Best director - Marianne Elliott and Miranda Cromwell (Death Of A Salesman)
Best actor - Andrew Scott (Present Laughter)
Best actress - Sharon D. Clarke (Death Of A Salesman)
Best supporting actor - Adrian Scarborough (Leopoldstadt)
Best supporting actress - Indira Varma (Present Laughter)
Best actor in a musical - Sam Tutty (Dear Evan Hansen)
Best actress in a musical - Miriam-Teak Lee (& Juliet)
Best supporting actor in a musical - David Bedella (& Juliet)
Best supporting actress in a musical - Cassidy Janson (& Juliet)
Best family show - The Worst Witch at Vaudeville Theatre
Best set design - Bob Crowley for Mary Poppins
Best lighting - Paule Constable (The Ocean At The End Of The Lane at National Theatre)
Best new dance production - Ingoma
Best new opera production - Billy Budd
Best costume design - Joanna Scotcher (Emilia)
Best sound design - Emma Laxton (Emilia)
Best theatre choreographer - Matthew Bourne and Stephen Mear (Mary Poppins)
Best original score - Dear Evan Hansen (Benj Pasek and Justin Paul, Orchestration by Alex Lacamoire)
Outstanding achievement in dance: Sara Baras for her choreography and performance in Ballet Flamenco - Sombras at Sadler's Wells
Outstanding achievement in opera - The Children's Ensemble for their performance in Noye's Fludde
Outstanding achievement in affiliate theatre - Baby Reindeer at Bush Theatre
Special award - Don Black