Once you have married the younger brother of the future king, what do you do next?

The Duke and Duchess of Sussex have secured deals with Spotify and Netflix, apparently worth millions of pounds, though it remains unclear exactly what they will be doing in return.

Meghan is now said to be considering some ‘very serious book deals’, from ‘numerous publishing houses’. From this, I take it to mean that it is the deals that are serious, rather than the books.

If Meghan wishes to take advice, there is only one other person in the world who has been in the same position, or, as they both might say, ‘followed the same amazing journey’.

This is, of course, Sarah, Duchess of York, who married the future king’s younger brother, Andrew, back in 1986.

Soon afterwards, Fergie — who recently became a grandmother as Princess Eugenie gave birth to a son — also secured a lucrative publishing deal.

”As a single mother with few assets and less income than most presumed, I was in deep financial trouble,” Fergie recalls in her autobiography.

In 1989, she published her first book, Budgie the Little Helicopter. As is often the case with children’s books, the illustrator did most of the work.

The text itself consisted of roughly 800 words — barely longer than this article. One page consisted of just four words — ‘Aaargh! Crash! Bang! Splat!’

A further five Budgie books appeared over the next six years. Then Fergie moved on to dieting books, including Dieting With the Duchess (1998) and Energy Breakthrough: Jump-Start Your Weight Loss and Feel Great (2002).

She then returned to children’s books, introducing a new character, a doll called Little Red. Little Red’s final book — Little Red’s Autumn Adventure — appeared in 2009, when it began to seem as though Little Red was little read.

Meghan is now said to be considering some “very serious book deals,” from “numerous publishing houses.”

By now, there was a vogue for children’s books tackling ‘issues’. Between 2007 and 2011, the Duchess put her name to a dozen of them, under the collective title of Helping Hands.

Prince Andrew’s former wife was once dubbed the “Duchess of Pork” by the press.

In a single year, 2011, she produced no fewer than five, including When Katie’s Parents Separated, Zach Gets Some Exercise and the double-billed Jacob Goes to the Doctor and Sophie Visits the Dentist.

How long will we have to wait for brand new Helping Hands books? Personally, I’m looking forward to Andrew Enjoys a Pizza and its follow-ups, Andrew Visits Jeffrey in New York, Andrew Chats With Emily and Andrew Keeps His Head Down.

Since April, the Duchess has been reading a book a day for children on a YouTube show called Fergie and Friends.

The readings all take under five minutes. She is filmed at home and dresses up, often with a garland in her hair. The shows have a slightly slapdash air: she clearly doesn’t believe in rehearsals. When things go wrong, she simply gurns.

On one of them, she had just started one of her own books — ‘It was a beautiful day at Buttercup Cottage, Little Red’s cosy cottage’ — when she interrupted herself.

“You haven’t to worry, they’re not very long books,” Fergie told her YouTube audience.

‘Do you know what, boys and girls, I’ve suddenly realized I’m not the same age as you and I’m going to have to put my glasses on. Here we go!’

In some episodes she shows children how to make things, such as ‘scrumptious, dumptious, diddly-umptious’ Traffic Light Sandwiches.

These creations often involve sharp knives and pointy cocktail sticks. ‘Ask Mummy and Daddy to help you with these big knives, please. Don’t want any trouble there, do we? No!’

Fergie herself is prone to be butter-fingered. Showing us how to create Flying Sausage Rockets, she nearly came a cropper. ‘You’ve got to take great care because you wouldn’t want to put the engine through your hand, which I nearly did!’

Fergie’s first Fergie and Friends show, back in April, has attracted just over 19,500 views. But her first reading of Little Red, uploaded a few days later — ‘This is Little Red! This is my fun friend and she’s fabulous!’ — has, at the time of writing, totted up only 5,263.

In My Story, Fergie describes how on her first-ever visit to Sandringham, she accidentally kicked one of the resident corgis when curtsying to the Queen.

Her show in June about making Fairy Wings out of leaves and cardboard has registered 1,931 views. And numbers for when she made Pixie Dust last September — ‘Glasses on, wings on, ready to fly!’ — are down to 639.

For a Halloween special she made Severed Fingers, carving fingernails out of frankfurters — ‘yum!’ — with her sharp knife. YouTube has registered 451 views.

But Fergie carries on, undaunted. Last week, she donned antlers to read from Scratch and Sniff: The Unicorn Fart Book, with plenty of animated sniffing and gurning. It has so far garnered 459 views.

Is this the sort of thing the Duchess of Sussex will be getting up to, 30 years from now?

Craig Brown is a columnist for the Daily Mail and the author of One Two Three Four: The Beatles in Time