“I’ve found a new reason to watch EastEnders,” Catharine Evans told me as she prepared for her role as Eliza Doolittle in next week’s Oxford Operatic Society show at the Playhouse.

Perhaps surprisingly, the OOS has put on My Fair Lady only once before, in 1995; so those Cockney vowels are long unheard. And Catharine is doing far more than learning how not to speak proper: “Although Eliza is largely uneducated at the beginning of the play, she is incredibly worldly-wise and she grows as a person throughout as she learns to be a lady. I have to try to portray this journey convincingly without it being too much of a cliché. There’s a change of accent, but also a change of body language and poise.”

At the heart of the musical — born out of Shaw’s play Pygmalion — is the relationship between Eliza and the mentor who discovers her in Covent Garden, Professor Henry Higgins. In this production, Charlie Ross reprises the role he created for Oxford Operatic 14 years ago, but one that had enchanted him since 1959: he saw the original London stage cast: “It was my first visit to the West End. Rex Harrison, Julie Andrews and Stanley Holloway were all larger than life . . . and the music! It was one of those shows when you spent all your time afterwards singing the numbers.”

I asked Ross if every Higgins these days has to do the role in Harrison non-singing mode, and he corrected me: “In the film, Harrison pitches the notes perfectly well when he needs to — for example in The Rain in Spain. And in the latest West End production, Jonathan Pryce sang more of the role. It’s just that most of the numbers sound better when spoken — Why Can’t The English? and Hymn to Him.”

Inevitably, for those who didn’t see the original stage production, it’s the Harrison-Hepburn film of My Fair Lady that hovers mightily. Dave Crewe, who directs this production for OOS and is responsible for the musical staging, is well aware of the problems: “It creates expectations from an audience. But though the performances are so iconic in people’s minds, I don’t believe it’s a good idea to try to just reproduce them: that’s almost impossible. I’ve tried to encourage the actors to go back to the text and find reason and pointers from there.”

Which seems to have worked, at least for his lead performers: Ross says Dave Crewe has made Higgins more approachable and less severe; Evans told me that he’s tried to draw “a very real and individual” performance from her.

And Crewe, who has clearly thought this through very carefully, goes further: “More than other musicals, it has very real people in it, with realistic settings and interactions. To do that justice, I’ve tried to focus on the two fundamental elements: the transformation of Eliza — not only from flower girl to lady but from being an unloved, insecure girl to being a confident, graceful woman — and secondly, establishing a credible base for a relationship between her and Higgins.”

I put it to Catharine Evans that Eliza must end up a little in love with the professor.

“We discussed this a lot during rehearsal! Initially, he treats her quite badly, seeing her as not much more than a bet with his colleague Colonel Pickering. But then everything changes. Does Eliza reciprocate his feelings? I believe there is an attraction — whether it be romantic, friendship or just the fact that they’ve simply met their equal in life.”

This production is a big one: the cast is some 55-strong, with an orchestra of almost 20 players.

David Crewe, whose sixth production this is for the company, is unsurprisingly enthusiastic: “We are very fortunate that we regularly get lots of people applying to join the society. It’s important to keep fresh with new talent, but we’re so lucky to have loyal members who’ve been with us, in some cases, for over 40 years.”

Charlie Ross — a professional auctioneer and well known for TV appearances on Flog It! — is certainly committed: he told me he’s had to turn down a total of eight auctions “in order to be on parade for rehearsals”.

And Catharine Evans, an interior designer now (after spending some years researching cat foods) is just delighted to be involved: “I guess, as my fiancé would say, I’m one of life’s Mr. Toads — poop poop! There are so many things I want to try.”

Wouldn’t it be loverly? I’m really looking forward to next week.