Theatre actress Patti LuPone has credited former Britain’s Got Talent runner-up Susan Boyle for Les Misérables reaching its 30th anniversary.

Susan Boyle singing I Dreamed a Dream from Les Misérables on her debut on The X Factor in 2009.

Boyle appeared on the TV talent show in April 2009 singing I Dreamed A Dream, a song made famous by LuPone in her role as Fantine in the musical’s original cast.

Speaking ahead of Les Misérables’s 30th anniversary gala, LuPone said: “I was told by Trevor Jackson (executive producer for Cameron Mackintosh Ltd) that Susan Boyle was the one that turned this around.

“It wasn’t necessarily limping but it may not have lasted the 30 years, and Susan Boyle, by singing that song, created another fever around it. I got a lovely royalty cheque so good for Susan Boyle!”

“What can I say? Good for Susan Boyle. It was surprising because she was a mess and suddenly she opened her mouth and it was like, ‘Good for you, girl!’” she added of the Scotswoman’s talent show performance.

LuPone was among the former cast members who joined the current company for a spectacular finale of One Day More at Queen’s Theatre to celebrate the musical’s record-breaking anniversary.

The critics panned it but the people voted with their feet

Thirty years to the day after taking the stage at the Barbican Centre, Colm Wilkinson, Roger Allam and Frances Ruffelle also reprised their roles as Jean Valjean, Inspector Javert and Eponine respectively for the gala in aid of Save the Children’s appeal for Syrian children.

A choir of 126 Welsh schoolchildren flanked the audience, having been picked by producer Sir Cameron Mackintosh from the musical’s school’s edition programme for the dramatic climax.

Former Jean Valjeans, John Owen-Jones and Geronimo Rauch also returned to celebrate the record-breaking milestone.

Colm Wilkinson came out of retirement to reprise his lead role and reminisced about their first performance, which was panned by reviewers.

“The critics panned it but the people voted with their feet. There was a void for this kind of thing, people reached out, they embraced it. They hadn’t seen anything like this before,” he said.

Ruffelle said the cast had no idea how abiding the musical would become and admitted that replaying the role was still “nerve-racking” years later: “We knew we were in something really special, but if someone had said this would last 30 years, it wasn’t something you could imagine.”

Proving the producers also underestimated the phenomenon it would become, Wilkinson was offered the lead in Phantom of the Opera at the same time, and told by Mackintosh: “If Les Misérables doesn’t work, you can do the Phantom.”

Some 450 tickets for the special gala were made available through a lottery and charity auction to raise money for child refugees inside Syria and across the region.

Based on Victor Hugo’s novel and with a score by Alain Boublil and Claude-Michel Schonberg, Les Misérables opened at the Barbican Centre in London on October 8, 1985, and has now been seen by 70 million people worldwide in 44 countries and 22 languages.