Christina Johnston announced on her live stream that she would be doing a real outdoor concert 'Opera in the Park' at Wherstead Park, I knew it would be worth the two-hour drive. Add to that the fact that it would be my first real concert in nearly five months, and it didn't take too much persuading for me to book.

Arriving at the entrance to the venue, I waited for one couple in front of me to check-in, then was greeted by a lady wearing a large face visor, who asked my name. She found me easily on her list and cheerfully informed me that I had the best seat in 'the house' – front row nearest the stage.

She asked if I had seen Christina before and seemed delighted with my response; I had seen Chrissy two years ago at Framlingham, and a couple of times since in guest appearances in London. The concert had been reported as a sell-out, so I asked how many tickets had been sold.

The answer was just 53! Was it financially viable at that number? I asked, and apparently it was – just. The lady then directed me towards a gentleman on the other side of the rose garden, who would show me to my seat. As I walked away, I heard her giving him my details by radio.

I was shown to my seat at a small table about 6m from the stage and a few meters to the left of the central aisle. The front row consisted of just four of these small tables, with ample separation between them. The second row comprised groups of two or more chairs at makeshift tables made from a stack of wooden pallets topped with a tablecloth. The rows formed an approximate half ellipse around the front of the stage. The third and final row was similar but included a few larger groups. Each group/table was provided with an individual parasol – very welcome as it was a hot summer afternoon. There was at least 4m separation between each group of seats.

Since the government guidance is to maintain at least 2m separation from others I did think that they could have maybe admitted a somewhat larger audience, but at least the wider spacing gave the waiting staff ample space to move between the groups without getting too close to anyone. The stage itself was a low platform placed at the front of a large open-fronted tent-like structure described as a tepee. Looking behind me, I was delighted to see my friends Philip and Fatima (who

I have met at numerous concerts around the country) sitting at the closest table, already tucking into their luxury picnic. They had also traveled quite a distance to be there, and I ascertained that they had not seen Christina live before, having only discovered her online during lockdown.

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At the appointed hour, the organiser came to the stage and welcomed the audience to the first event of the year at Wherstead Park. He then continued, introducing Christina Johnston. As he left the stage, the strains of Handel's Lascia Ch'io Pangacame drifting across from the PA system but the stage remained empty. After a couple of lines, I heard Christina's clear soprano voice joining in with the music, and turned to see her making her way across the lawn from the mansion behind us.

Christina paused at the top of the steps to the center rear, wearing a gorgeous ice blue dress with a full layered skirt and embroidered top. As she lifted her skirt slightly to negotiate the steps, I noted that Chrissy had sensibly chosen to wear flat-soled sandals rather than high heels. Christina finally reached the stage, where she stood to finish the aria.

The next song was Puccini's well-loved O Mio Babbino Caro, sung by Christina with wonderful expression, followed by the delightful Ah! Je Veux Vivre from Gounod's Romeo and Juliet.

We then had a break from opera and ventured into the world of film music with the wonderful theme from Cinema Paradiso by Ennio Morricone. I think it was during this song that the thought was brought home to me – how I love classical crossover music, and how much I have missed it. Although I have come to appreciate and enjoy other musical genres, there is nothing that lifts my heart quite like classical crossover, and Christina is one of the best I know to deliver the music that I love. This was my first live classical crossover vocal concert of the year; every song so far had been exquisite and filled me with joy – and so it continued for the rest of the afternoon.

Christina explained that, after graduating from the Guildhall School of Music and Drama in London, she had moved to Prague where she began her professional music career. The next song was one that she had learned in Prague – the gorgeous Song to the Moon from Dvorak's opera Rusalka. Christina sang this in the original Czech language and it was one of the most moving moments of the afternoon. Many of the backing tracks had been recorded by the City of Prague Philharmonic Orchestra, and at various points, during the afternoon Chrissy would joke that they were sitting behind her playing. Although there was indeed room for a modest orchestra in the tepee behind her, the space was mostly empty and all the musicians seemed to have chosen to sit in a little black box on the technician's table.

Moving on to the world of musical theatre, we were treated to Greenfinch and Linnet Bird from Sweeney Todd and I Could Have Danced All Nightfrom My Fair Lady. Christina is adept at portraying different characters in her performance and these songs were full of life, with a great sense of fun in the latter number. This section was rounded off with Think of Me from Phantom of the Opera – a beautiful performance throughout with those high cadenzas at the end delivered perfectly and seemingly effortlessly in Christina's high coloratura voice.

The final song of the first half was simply breathtaking and left the audience gasping for more. This was The Nightingale, originally written by the Russian Composer Aleksandr Alyabyev and adapted as a showpiece for the lyric coloratura soprano. Christina excelled in every aspect of this challenging work, the piccolo birdsong at the end perfectly echoing Christina's pure voice. I recall this song also being one of the most outstanding and memorable tracks from her debut album 'Blessing'.

The second half commenced without announcement, and suddenly Christina was back on stage in another gorgeous dress – this one with a pure white full skirt and a floral pattern bodice.

The opening song was Voi che sapete from Mozart's Marriage of Figaro. Although originally written for a male role, the song was also well suited to Christina's voice. Apparently she has recently recorded this for the soundtrack of a major film, soon to be released.

In another cinematic interlude, we heard the wonderful Moon River from Breakfast at Tiffany's. Audrey Hepburn was one of Chrissy's idols when she was a child, but she recently learned that all the songs on this film were dubbed voice-overs, so she had not heard Audrey singing at all.

Back to Mozart – one of Christina's first major stage roles in Prague was the evil Queen of the Night, in The Magic Flute, and she delivered the famous aria Der Hölle Rache with great dramatic effect. Often considered as one of the most challenging arias for a soprano, Christina's control of the high notes seemed to be effortless.

Next came the theme song from Love Never Diesby Andrew Lloyd Webber, and I don't think I have ever heard a more moving performance of this song.

Another fun number followed – The Doll Song from Offenbach's Tales of Hoffmann, in which Christina perfectly mimicked the mechanical movements of a not-so-well-behaved wind-up doll.

Then came a lovely performance of Memory from Cats.

Christina explained that although as a coloratura soprano her vocal range extends up to high C7, she would sometimes have difficulty with the lower notes in some songs, including the following Never Enough from The Greatest Showman. She need not have worried – although she may not have the same power in her lower range, the notes were still there in perfect tone. Her clear enunciation in the higher parts of the song was a joy to hear, avoiding the distortion that sometimes comes from other singers struggling to reach the notes.

Sadly the concert was now drawing towards its close, and perhaps some of that sadness was reflected in Christina's emotional rendition of I Dreamed a Dream from Les Miserables.

The final song was another fun piece, allowing Christina to show off her character acting skills as the (never) self-effacing Galinda the good witch in Popular from Wicked.

Okay, the final song in a concert is rarely the last, and the audience reaction was sufficient for Christina to launch into her encore – a sparkling performance of Glitter and be Gay from Bernstein's Candide, followed by rousing applause and a standing ovation from the audience.

Through her regular on-line streamings in lockdown, Christina's confidence in presentation, and talking between the songs has grown from week to week, in what she has freely admitted was a difficult area for her at first. Faced with a live audience for the first time in months, all traces of self-consciousness seemed to vanish and she was the perfect hostess. Her introductions between songs were witty and informative, including parts of her own life story, and I got the impression that she was enjoying the whole experience just as much as her appreciative audience.

After going to change, Chrissy returned to the arena and made herself available to chat to all members of the audience (maintaining the appropriate social distancing) making a lovely end to a perfect afternoon.

John Harvey is a regular reviewer in the Classical Crossover magazine, where this was first published, in a slightly longer version, which includes other gigs.