Another day, another celebrity announces they are to “pen” a children’s book. Already this week, Jamie Lee Curtis has announced a “selfie-themed” tome, Chelsea Clinton a picture book about inspirational women and the Black Eyed Peas a graphic novel featuring zombies.

They join a slew of celebs cashing in on a burgeoning market. In the past month, model-turned-actor Cara Delevingne, TV presenter Dermot O’Leary and even politician and professional motormouth George Galloway have joined Frank Lampard, Danny Baker, Julian Clary and Fearne Cotton in vying to be the next JK Rowling.

Though publishers are notoriously cagey about money, industry sources say the advances paid to celebrities are considerably higher than the amounts usually doled out to children’s writers, whose contracts are won on talent rather than fame. Which explains the resentment many authors feel towards these incomers.

One prize-winning writer, who didn’t want to be named, left her last publisher after a new media star received a huge advance for a ghostwritten novel that consequently bombed. “The massive advances mean publishers put all their marketing into making these books work in order to earn back the investment,” she says. “So when they fail, not only have they taken money for publicity that could have helped the rest of us, but there is no money left.”

Celebrity-penned children’s books are nothing new. From Madonna’s English Roses and Sarah Ferguson’s Budgie the Helicopter, stars more familiar with Hello! than Harry Potter have landed deals that seem tied to status rather than storytelling ability.

Some have done very well. Though there was a degree of sniffiness in the publishing world when comedian David Walliams signed a book deal, few would now deny that HarperCollins made a smart investment. His stratospheric sales have made him one of the three highest-earning authors in the UK, clocking up print sales of £11m.

But such successes have only led to more dominance, says children’s writer Fiona Dunbar. “Some years ago I blogged on this subject, saying, ‘It’s fine, everybody chill out, it’s good for the industry generally,’” the Divine Freaks author recalls. “But now it’s different, because the scale has increased so much.”

Lucy Coats, who has written both picture and story books for children, agrees: “The number and frequency of recent deals is making many of us consider our involvement in the business. It’s depressing to say the least.”

Authors understand the attraction of star names: celebrities have built-in reach through TV and social media platforms. If even a fraction of their followers buy their book, they have a hit on their hands.

And some authors are doing good business as ghostwriters, which can promote their own work, too. Though Walliams writes his own novels, others, such as Olympic cycling champion Chris Hoy, openly use ghosts. Hoy’s Flying Fergus series has ridden to the top of the charts powered by Joanna Nadin, a former Labour party speechwriter and the author of a series of her own.

Employing an established children’s author as ghostwriter can have a double effect: the writer benefits from exposure to a bigger audience, while the star benefits from the writer’s credibility. No wonder Delevingne’s people were emphasising the involvement of Rowan Coleman – bestselling author of We Are All Made of Stars – with the model’s forthcoming YA novel Mirror, Mirror?

But the balance of such deals remains tipped steeply towards the celebrity. Some are undoubtedly well crafted but others are little more than another addition to the personal brand, to go alongside the perfume, fitness DVD and fashion label.

Surely children’s books – which help form our outlook on life, which we carry into adulthood and old age – deserve better?