Oscar-winning actress Emma Thompson has revealed her recent stage comeback in New York was a "beautiful, inspiring" experience that brought her to tears.
"It was magical to be in front of an audience again," she said of her role in Stephen Sondheim's Sweeney Todd at the Lincoln Center. "It made me weep."
Thompson and co-star Bryn Terfel will reunite in 2015 when their production is revived at the London Coliseum.
The semi-staged production will have a limited run of 13 performances only.
Thompson said it was "like a dream coming true" to be invited to bring Sweeney Todd to London following its five-performance run in New York in March.
"It was so terrible to think of it ending," explained the actress, who plays eccentric pie-maker Mrs Lovett to Terfel's serial-killing Demon Barber of Fleet Street.
The 55-year-old, who has won Oscars for both acting and screenwriting, said she was hoping there would be "a slight improvement" when she reprises her role next March, "and by that I mean no nausea".
"If I can manage the fear without the nausea I'll be fine," she continued, describing Sondheim's Tony-winning score as "very difficult and fantastically complex".
Welsh bass-baritone Terfel described the role of Todd - recently played on stage by Michael Ball and on film by Johnny Depp - as "an incredible vocal vehicle".
"Sweeney is definitely, undoubtedly operatic," said the 48-year-old, who likened the part to Scarpia, the sinister chief of police in Puccini's opera Tosca.
"I defy anyone to sing his Epiphany without thinking that is a very difficult aria to perform," he told reporters on Tuesday.
Sweeney Todd is the first production to result from the English National Opera's partnership with commercial producers Michael Grade and Michael Linnit.
The staging of modern musicals alongside its operatic repertoire is intended to generate extra revenue for the ENO and help secure its financial future.
Speaking at a press conference at the Coliseum, Lord Grade said the plan was to present shows "as good as anything in the West End".
John Berry, the ENO's artistic director, said the show would be staged at a time of the year when the Coliseum usually hosts visiting productions.
Thompson last performed in the West End in 1989 in John Osborne's Look Back in Anger, in which she appeared with her then-husband Kenneth Branagh.
She was previously seen alongside Robert Lindsay in Me and My Girl - a musical whose relentless cheerfulness, she joked on Tuesday, had left her "clinically depressed".
Terfel and Thompson are likely to be the only members of the New York Philharmonic's presentation to reprise their roles in the capital.
Sweeney Todd: The Demon Barber of Fleet Street, by Stephen Sondheim and Hugh Wheeler, will run from 31 March to 12 April at ENO's London Coliseum.