AS reinventions go, it is perhaps not quite in the Charlotte Church class, but Katherine Jenkins – the older Welsh soprano by six years – made a significant step in 2017 when she appeared in English National Opera’s production of Carousel in the spring.

When the casting of Jenkins as Julie Jordan, alongside Alfie Boe as Billy Bigelow, was announced there were many naysayers in the opera world. The semi-staged musicals at London’s Coliseum had already been derided as a cynical cash-cow project from the perennially financially-stretched company.

Jenkins was following in the footsteps of Glenn Close in Sunset Boulevard and Emma Thompson in Sweeney Todd (whose co-star was Bryn Terfel), so it was a bold undertaking for someone previously derided as a the sort of “opera singer” who had never actually appeared on stage in an opera.

In the event, and although Boe fared less well in the press, the limited run of performances was an undisputed triumph for ENO and especially for Jenkins, whose acting was as lavishly praised as her singing in reviews generally written by theatre critics.

Jenkins confesses to having been very nervous about taking it on. “It was loads of things I have never done before: a theatrical show; acting; an American accent. It was a huge amount of work.”

Jenkins concurs that the term “semi-staged” is a bit of a nonsense. It was “fully staged” as far as she was concerned, and that seems unarguable of a show that was costumed, and featured an enormous chorus and an orchestra of more than 40. With 100 people involved and a stage that was far from bare of props and set, in April and May of this year it was the largest company in any theatre in London – and tickets were £150.

The production had a full six weeks of rehearsals before it opened and Jenkins spent a fortnight before that working on that accent and her acting skills.

She was also very careful to “be in top health” for a schedule of eight shows a week that was more than she had ever undertaken before. The show may have played for a limited season, but it still had 50 performances.

It is that aspect of the undertaking that means there is currently no further musical theatre in Jenkins’s diary – carving out that amount of time in a programme of concert work that already stretches into the foreseeable future is not easy.

“I have to make sure I choose the right thing for me,” she says, before suggesting that the next time she undertakes a full musical it might be a premiere.

“We are talking about the possibility of a new thing,” says Jenkins, “but that will be two or three years ahead.”

It will be no surprise, however, if a song from Carousel finds its way into Jenkins’s show at Glasgow Royal Concert Hall on December 20, even if that is not the direction she has planned for that show.

The Glasgow date kicks off the run of seasonal concerts at the Glasgow venue from promoter Raymond Gubbay, which include the RSNO’s Hogmanay bash with tenor Jamie MacDougall and a night of film music by the national orchestra entitled Zimmer vs Williams.

Anthony Inglis will be conducting the Scottish Concert Orchestra, a scratch band of top freelance players, for Christmas with Jenkins, which the singer says will be all about setting up the spirit of the season.

She is on the road with the show across the UK from the first of the month at Leicester’s De Montford Hall, with young Australian tenor Mark Vincent as her vocal foil, and she promises a repertoire that will be a little different from the concerts she has performed previously at this time of year.

“I will be including songs that people know really well, but also some different things that I haven’t been doing all my life. So we’ll have some traditional Christmas songs but also pop songs, not just classical.

“And there will be carols like Silent Night, Hark the Herald and Come All Ye Faithful,” she adds, perhaps mindful of her role as a regular presenter on BBC TV’s long-running Sunday show, Songs of Praise.

“I always think of people getting prepared for Christmas and all the work that can be, so I have a responsibility to get them switched on for all of that.”

With her first child, Aaliyah, now two years old, excitement for the season is not hard to locate at Jenkins’s London home with husband Andrew Levitas, although the singer will not be back from her tour to share it with her daughter until three days before Christmas.

“She is very excited for Christmas, and we have been learning songs,” says Jenkins, although she quickly refutes any notion of training the toddler to follow in mum’s footsteps.

“Oh no, I’d never put any pressure on her. And at what age can you tell if someone is going to be musical? I suppose I was singing when I was four . . . ,” she muses.

Jenkins is happy to enthuse about the benefits of motherhood though, and would like to extend the family “at some point”.

“It has made me a better, calmer and happier person,” she states unequivocally.

That perhaps includes a certain equanimity about what is said about her in the media, both personally and professionally.

“The reviews of Carousel were very unexpected. I was prepared to be written off as some modern Florence Foster Jenkins – I was pretty convinced they wouldn’t say nice things.”

By the same token she is unperturbed by the cynicism about her being an “opera singer” despite her Royal Academy training and sharing stages with Terfel, Jose Carreras, Kiri te Kanawa and Rolando Villazon.

“That’s been going on in the background for so long. It never bothered me in the beginning and is doesn’t bother me now – you can’t please everyone.”

The day after we speak she is performing a concert in Moscow, which she sees as being much more in the mainstream of what it is that she does, performing arias from everything from Carmen to Phantom of the Opera with an orchestra, alongside arrangements of folk songs – what she calls, distinguishing it from the show she’ll perform in Glasgow next month, “a classical concert.”

“Classical music is seen as an elitist art form, but it was the pop music of its time. It was written for the masses,” she says. Bringing that music back to the mass audience is what Jenkins sees as her job.

Being Welsh is an obvious asset in Jenkins’s book. “The ‘Land of Song’ is a real thing. We tend to find each other when we are out on tour in the world, and it is amazing that there are so many globally-known voices from such a small place.”

“I think the reason for it is that people are not embarrassed about getting up and singing – at the rugby or in the pub. And that is a Scottish thing too.”

Christmas with Katherine Jenkins is at Glasgow Royal Concert Hall on Wednesday December 20.