Prince Harry and Meghan plan to split their time between the UK and North America - and their global reach could open up a wealth of opportunities.

But any move into the private sector and the monetisation of the Sussex brand would pose challenges for the royal couple.

"The established rule has always been that if you are a working royal, you don't really do paid work - that one excludes the other," says BBC royal correspondent Jonny Dymond.

"Nearly any employment of the type they are going to get is open to the charge that they are monetising or exploiting their royal brand."

If the couple renounced their royal titles, that would give them more freedom - but there's no suggestion they want to do this.

So far, they have focused on their plans to launch a new "charitable entity". But what opportunities might there be for commercial ventures?

Book deal

While the couple have spoken about their struggles with the intense media interest in their lives, the idea of revealing more about themselves in their own words might be more appealing - and lucrative.

The 2017 book deal signed by Barack and Michelle Obama was believed to be worth more than $60m (£48m).

It's also an area Meghan has previously shown an interest in. In her introduction to last year's September issue of Vogue, which she guest edited, Meghan wrote of her "love of writing".

Before she married Harry, she also ran a lifestyle blog, The Tig, where she shared beauty, fashion and travel tips.

Natalie Jerome, a literary agent at Aevitas, says the couple have "enormous power and reach" and any book deal would be extremely lucrative.

"People have compared them to the Obamas and I think there's potentially some merit in that," she says.

Meghan is an aspirational figure for many women of colour and young people, she adds.

"We're in a period now where we're talking increasingly about diversity within publishing and there's a real push to reach wider audiences," she says.

"If she were to publish a book in her own right and reach out to young people on the ground by doing talks and going to schools like Michelle Obama did, I think the book would be hugely successful."

TV and film

As well as potentially sharing more about their own lives, Harry and Meghan could also turn to causes they are passionate about for material.

For Meghan, these include equality and women's rights, while Harry has been vocal in campaigning on mental health and veterans.

The pair could choose to follow in the steps of the Obamas, who set up their own production company before signing a deal with Netflix, with projects including documentaries addressing social and political activism.

Harry has already teamed up with US media mogul Oprah Winfrey on a series addressing mental health for Apple TV, which is due for broadcast in 2020.

Could there be more TV opportunities in the pipeline?

Meghan, of course, first found fame as an actress, starring in the TV drama Suits.

She gave up her former career when she joined the Royal Family - but if she chose to return to acting she would surely be in high demand.

Public speaking

Another potential avenue for the pair to explore could be after-dinner speeches and events.

Jeremy Lee, director at speaking agency JLA, says if they maintained a positive profile the couple could earn six-figure sums for each appearance.

He predicts demand would be higher in US, where Mr Lee says the pair could earn up to $500,000 (£380,000) per engagement.

However, he says companies in the UK would be more sensitive to reputational risk if public opinion turned against the couple.

Mr Lee predicts UK companies would only be willing to take the royals as speakers at an event linked to one of their campaigning interests, in return for a donation to their charitable foundation - rather than a fee - in the region of £100,000.

But in the US, there would be interest from "anybody that wants to show off and has got the budget", he says.

Commercial partnerships

Whether its a designer handbag or Archie's hand-knitted bobble hat, whenever the Sussexes are pictured with a product, sales go through the roof.

"Any brand on the planet would want to work with them," says journalist and royal style commentator Elizabeth Holmes. "I think it's a question of what they want to do."

Ms Holmes suggests any commercial partnerships would be tied to the couple's charitable causes, perhaps with a secondary opportunity to raise personal income.

For example, Meghan is the patron of a charity that provides free clothing and interview training to unemployed women and has launched her own clothing line for the organisation.

"Meghan really understands the power of fashion," Ms Holmes says, using her choices to promote smaller brands owned by women, often with a sustainable ethos.

However, that doesn't mean we should expect the couple's 10.5 million Instagram followers to be suddenly bombarded with sponsored content and product placement, Ms Holmes says.

While the royal couple have a huge platform, it pales in comparison to the likes of Kylie Jenner, who has more than 150 million Instagram followers.

The reality TV star, who topped last year's Instagram rich list, is estimated to earn around $1.2m (£960,000) for a single sponsored post.

Could Meghan and Harry follow that trend? Ms Holmes says: "I don't think that's necessarily an appropriate thing for a member of the Royal Family."

In June last year, the duke and duchess also applied to trademark the "Sussex Royal" brand across items including books, calendars, clothing, charitable fundraising and campaigning.

This opens up the option of launching their own brands, from beauty products to clothing lines. However, any move that could be seen as exploiting the royal brand would be likely to promote criticism.

Ms Holmes says this is a real risk in any commercial venture, adding: "That's why I think they'll be careful about it."