To many people in the United Kingdom, crime writer Agatha Christie's work is so familiar it is easy to take it for granted, but 49 years after her death, the woman known as the Queen of Crime reigns unchallenged worldwide.

Every year, new audiences find Christie, whose 66 novels, 14 short story collections, and numerous screen and stage adaptations are reputedly outsold only by the Bible and the complete works of William Shakespeare.

London is currently home to two of Christie plays: the world's longest-running stage production, The Mousetrap, which recently passed its 30,000th performance, and Witness for the Prosecution, a murder trial drama staged in an old courtroom in London's County Hall.

Its immersive staging is a theatrical experience like no other, with Christie constantly wrong-footing the audience with plot twists before the play's dramatic conclusion, which is often greeted with audible gasps.

Last year, Witness director Lucy Bailey took another Christie thriller, And Then There Were None, on tour to China, and two members of that touring cast are now in Witness in London.

"Going to China was a complete shot in the dark for all of us, but it was a delightful surprise," said Jonathan Firth, who plays barrister Wilfrid Robarts in Witness. "I got the impression Christie might be more highly regarded in China than she is in the UK. Here, she's part of the national DNA, but she's not considered a towering literary figure."

Recently, Chinese audiences got their first official Christie show when streaming platform iQiyi released Checkmate, which is based on stories involving arguably her most famous creation, Belgian detective Hercule Poirot.

"In China, people were asking us to sign copies of And Then There Were None, and also her biography," said Firth. "I've done over 300 performances of Witness here and that's never happened, but it was not uncommon in China, so the Poirot updates don't surprise me."

Another of the tourists now playing in Witness, Jack Spencer, said he was impressed by Chinese audiences' familiarity with Christie's work, and the fact they did not have the preconceptions of British audiences, which forced the cast to view Christie's work through fresh eyes.

"In China, you're not playing to the level of audience expectation and stereotypes you'd encounter at home — they take the work, and the craft and workmanship that goes with it, on face value, which makes us tell the story authentically, without that baggage," he said.

Spencer said the experience of playing in China had changed how he does his job.

"Some people are surprised Witness is still selling out after eight years, but this way of thinking is why," he explained. "It highlighted the value of seeing past stereotypes and appreciating the text, which is something I've tried to take to everything I do.

"Christie's stories still sell all over the world, and there's a reason why — so lose the baggage, do your work, and you'll create something much more believable."