For there was something about the gun-slinging, whip-cracking frontierswoman first immortalised on screen in 1953 by Doris Day that Fletcher’s mum knew her daughter was born to play.
So, when the offer came through, the 32-year-old performer found she just couldn’t say no.
“My mum had always said I would be a good Calamity Jane and through the entirety of my adult career she has always said she would love to see my playing the part,” Fletcher says, taking a break from rehearsals ahead of the tour kicking off in January.
“It’s her dream role for me. So I looked into it and listened to the songs and watched the movie starring Doris Day and fell in love with it.
“Doris is such an icon.
“Though I did have to prepare my mum not to get her hopes up as things do fall through and you never know what might happen.”
Fortunately for both Fletcher and her mum, things did go according to plan, and she is now set to tour the country in the iconic role, which has also seen the likes of Carol Burnett, Barbara Windsor, Toyah Willcox, Jodie Prenger and even novelist Lynda La Plante all have a crack – excuse the pun – of tackling the fearless heroine.
Fletcher is a worthy addition to that list, however.
As one of theatre’s brightest stars, she has appeared in some of the biggest productions of recent years, not least Les Misérables and the lead in Andrew Lloyd Webber’s Cinderella – a role she originated.
Playing Calamity, however, is a dream of a role because of the way it pushes her as a performer.
“I am relatively new to the whole world of Calamity Jane, but it’s a dream role in terms of her as a character,” Fletcher explains.
“She is romantic lead, gets a great love story, has an amazing female friendship with Katie Brown and gets all the cracking, belty numbers.
“She ticks all of those boxes and it’s so wonderful she’s not just an ingenue or the soppy romantic or just a comedy character, she is all of it.
“Parts like that are really rare and she has been great fun to get to know.”
Fletcher says that the Calamity Jane is a “gun-slinging, whip-cracking woman prone to making a few blunders and mistakes”.
The show is also about femininity, she adds, particularly around her relationship with Wild Bill Hickok, portrayed on stage in this production by Vinny Coyle, but made famous on screen by Howard Keel.
“There are conversations between her and Wild Bill where he says ‘Why can’t you be more feminine?” Fletcher explains.
“She goes through a Cinderella story finding it, but ultimately ends up going back to who she is comfortable as, and being loved and accepted for it.
“And it’s all hidden within this funny, farcical story.”
The musical features songs such as The Deadwood Stage (Whip-Crack-Away) and Secret Love, all of which Fletcher is relishing getting to learn and sing.
To many, the score will be best known for being sung by Day, and there may well be fans of the musical who can’t imagine the role being played by anyone else.
For some performers, that could be a daunting prospect, but Fletcher is not afraid of the task ahead.
“I have a good mindset about the pressure that comes with that,” she explains. “You can’t please everyone as everyone has different versions of what they want the character to be.
“If you tried to please people, you would come up with this warped version that isn’t anyone’s dream version.”
She adds: “I feel like I have been entrusted with the role and I need to be the one to decide who this version of Calamity Jane is.
“And if people don’t like it, they don’t like it. But if they do, it means all the more.”
Fletcher’s down-to-earth nature and easygoing attitude is a product of her upbringing.
She grew up in Harrow, north London, the daughter of parents who were, in her own words, “very normal, hard-working people”.
Her mum was a learning support teacher at a primary school, her dad worked at a Kodak factory.
As a young kid, she watched her older brother, Tom (now of McFly fame) attend Sylvia Young Theatre School and star in Oliver! at the London Palladium.
Keen to try it herself, Fletcher did weekend classes at Sylvia Young’s and was also signed to the school’s agency.
Aged seven, she landed the part of young Eponine in Les Mis, before roles came along in Chitty Chitty Bang Bang and Mary Poppins.
She learned on the job, soaking up everything she could from her co-stars and was eventually signed to leading agency Curtis Brown.
Through them, Fletcher went on to be cast as the older Eponine in Les Mis (having already played the young Eponine as a kid) and her path to musical theatre stardom was set.
But while Fletcher may have followed in her bother’s footsteps, initially, it now seems he is following in hers.
The McFly frontman has recently penned The Creakers, a brand-new musical, and is also about to work on a musical based on Paddington.
“It has been amazing seeing Tom move into musical theatre,” Fletcher beams, admitting that she is still the “annoying sister”.
“People who have been in the most recent workshops of Paddington are good friends of mine, so it’s great to have our worlds merge like that.”
But if he has made the transition into theatre, does she see herself following him into the pop world?
“I don’t think it’s on the cards anytime soon,” she laughs. “I love theatre too much.”
Alongside her work in theatre, Fletcher also has a successful writing career, publishing a series of books for young people, and also has a huge social media following, beginning – as she did – by vlogging on YouTube.
Today, her YouTube channel has more than 500,000 subscribers, while hundreds of thousands also follow her on Instagram.
This, however, comes with a pressure of its own, one that Fletcher has had to navigate,
“There is no rulebook on social media, no rules, no one really knows what we are doing and what is okay and not okay,” she explains.
“And for those inclined to say whatever they want it has never been easier.
“They never watch you read how their comments affect you – or see the conversations you have with your loved one about this thing they said to you.”
She adds: “When I was in Heathers, someone in the cast logged on to their social media and saw this awful comment and it completely broke her.
“It made me look at myself and think ‘Oh my god, I am so desensitised to it’.
“How horrible we have just learnt to live with it.”
She says there is a “mindset” that if you put yourself in the public eye you should just accept what comes with it, the good and the bad.
“There is a level of expecting it but there should never be any accepting it,” she stresses.
“You know there will be people who aren’t your people and who have things to say about your appearance or performance but there should never be any tolerance of any behaviour like that.
“I got messages like that at 16 and they completely broke me.”
It was her mum, however, who helped her deal with the nasty side of social media.
“I remember her watching for signs of me getting negative comments, as when you are the sister of someone in a famous band, you are not just a 16-year-old with three followers you are a 16-year-old with links to this world-famous band and thousands of people follow you just because of who you are related to,” she says.
“It puts you in a very strange position.
“So my mum was good at saying ‘That is enough, close the laptop and we will go for a walk’. My parents are the best people.”
For now, Fletcher is all about Calamity Jane and the UK tour, which will see her on the road for the best part of a year.
It means she will be away from her husband, fellow performer Joel Montague, and their daughter, Mable, who will be one when the tour begins and will join her for some of the dates.
And if juggling motherhood and appearing in a major tour was not enough, Fletcher has also mastered a new skill while working on Calamity Jane.
Her cast mates in the show are actor-musicians, and – not one to be left out – Fletcher will also be picking up an instrument.
Albeit, a slightly unusual one.
“I got the coconuts to play,” she laughs.
“I am the horse. So while everyone else is incredibly talented with the saxophone and the trumpet and cello, I will be focusing on the coconuts.”
She adds: “They’re only used once so far, but I reckon they will make a reappearance.”
Calamity Jane is set to hit Sunderland Theatre from Tuesday, February 4 to Saturday, February 8, 2025.
Tickets start at £15 online and may be subject to a £3.95 transaction fee.
Book now at www.atgtickets.com/venues/sunderland-empire/