She is one of the biggest stars in pop, with a glittering career selling well over over 20 million singles and three million albums worldwide, a home in Los Angeles and a celebrity lifestyle.

But this self-confessed ‘Essex girl’ says she is most excited to be playing a show right here in Oxfordshire.

The Price Tag star takes top billing at Henley Festival tonight, in one of the biggest nights of the county’s musical calendar. And Jessie, who played the festival in 2015, can’t conceal her delight at coming back to perform on its Floating Stage on the Thames.

“I’m living my best life!” she says.

“I love Henley. I had a great time there last time I went. The crowd is great and all my friends and family are coming.”

She goes on: “I am grateful for the chance to play my music live for people coming back and people who have never been before.”

She has just flown in from LA, where she moved in 2014. The move was motivated partly by work opportunities but also by her dissatisfaction with the level of media attention she was getting over here – complaining that far too much of the focus was on her personal life rather than her music.

“I’ll be working in the UK for the next few months so I am excited to be back here, and around my friends and family,” she says.

She said moving to California gave her a taste of anonymity away from the paparazzi frenzy on this side of the Atlantic.

“Everybody needs privacy,” she says. “People in the UK have their ups and downs though and I’m not the only one to have been through it.”

The girl from Redbridge, where London slides into Essex, insists she has not lost touch with her roots though.

“I had a load of opportunities in America, but I’ve always had my place in London too,” she says.

“When I’m in America I never know where I am. I have a terrible sense of direction, but in London I know where I’m going. And there’s nothing better than the energy here. I’m an Essex girl born and bred!”

Jessie – real name Jessica Cornish – can barely remember a time she wasn’t in showbiz. By the age of 11 she had achieved more than most of us can hope to in a lifetime, by landing a part in the West End musical Whistle Down the Wind.

The Oxford Times:

She went on to hone her craft at Croydon’s BRIT School – which has also produced the likes of Adele, Amy Winehouse, X Factor star Leona Lewis, Katy B, Ella Eyre and The Kooks.

Her debut single Do It Like a Dude was a number two hit while follow-up Price Tag went double platinum and topped the charts in 19 countries – including here.

Her debut album Who You Are reached the top two of the album chart and gave us top 10 singles Nobody’s Perfect, Who You Are, Laserlight and the chart-topper Domino. It made her the first British female artist to have six top 10 singles from a single studio album.

She continued with second album Alive in 2013, which reached number three in the album charts and saw hits like Wild and It’s My Party. The following year’s third album Sweet Talker reached the top five here and the top 10 in America.

Read more: Cornbury Festival in pictures: The Beach Boys, Keane and The Specials rock 11,000 people

Her number one single with Ariana Grande and Nicki Minaj, Bang Bang, also went multi-platinum worldwide.

Her fame has seen her playing for the Queen at her Diamond Jubilee Concert at Buckingham Palace, the closing ceremony of the London Olympics and becoming a coach and mentor on the Voice. But it is tonight’s show for Henley Festival which is making her smile – not least the prospect of seeing her dad in evening wear at the black tie event.

“I’ll be in my hat!” she says cheerfully. “The whole family are coming and my dad is looking forward to it. It’s the dress code that makes it unique; I just hope it’s not p*ssing it down!”

So what can we expect to hear? “Lots you know, like Price Tag, but also some the audience haven’t heard.”

And does she get bored of singing her biggest hits? “I don’t get bored,” she says. “My fans know how much effort I put into making things different. Some songs are nearly 10 years-old – but most of the time the audience sing them for me!”

Read more: Kylie brings the love to Blenheim Palace

She said she would hate to go and see one of her own stars play live and not get their biggest songs.

“If I go to see Beyoncé, I want to hear Crazy in Love; it’s the same!” she laughs.

The small Oxfordshire market town and its well turned out denizens is a far cry from the scene of her latest success: China. The star took first place in the show China’s Singer, which pits professional singers against each other. She was among the first international performer to appear on the show, and won over the audience with hits Flashlight and Domino, and a cover of I Will Always Love You.

“It was unlike anything else in my entire life,” she laughs. “It is the biggest TV show in China and it was great to open a door to the world.”

She goes on: “I don’t take anything for granted though, and when I’m at my best is on stage.

“I enjoy the roller coaster of it all.

“Life isn’t easy and we have to help each other through the times. Some shows have been really emotional and some a laugh.”

She insisted that, despite all the trappings of fame, however, she is still the same Jessie.

“I am just a being a normal person,” she says. “I like to make sure I am always nice to people... unless they are not nice to me!”

And does she think she has been lucky?

“You make your own luck,” she answers. “No one can control your life as much as you can. I work hard and never ask for help. And people know how much I care. And I’m grateful that 10 years in I am achieving things no one believed would have been possible – like winning a Chinese TV show.

“I am trying to be a singer you can celebrate as someone who is representing the UK around the world.”

  • Henley Festival runs until Sunday, with headline shows by Jessie J, Tom Odell, Bjorn Again and a Classic FM concert: A Night at the Movies. See henley-festival.co.uk