Meghan faces a right royal learning curve

Belinda Tasker

Meghan Markle has made it clear she's keen to "hit the ground running" once she marries Prince Harry and becomes a senior member of the royal family.

Already known for championing a variety of causes from women's rights, racial equality and the need to end modern day slavery, the former actress is well rehearsed in lending her voice to a good cause.

But as a senior royal married to a prince who is sixth in line to the throne, she'll have to walk a careful line thanks to strict protocols.

Historian Dr Anna Whitelock says as head of state, the Queen has set the standard by adopting a strictly neutral approach to political matters.

"Prince Charles has always spoken out on issues that are important to him, such as the environment, and more recently the younger royals too with mental health and so on," Dr Whitelock told AAP.

"But there's a kind of line to walk between speaking out on issues and not being seen to be political and this is something Meghan is going to have to learn to navigate."

The 36-year-old raised eyebrows in Britain with comments she made when she joined Harry along with his brother Prince William and Catherine on stage for the inaugural Royal Foundation Forum in London in February.

"Right now, in the climate that we're seeing with so many campaigns - Me Too and Time's Up - there is no better time to really shine a light on women feeling empowered and people really helping to support them - men included in that," said the self-proclaimed feminist, who as an 11-year-old wrote to the then US first lady Hillary Clinton complaining about a sexist ad for washing up liquid.

Dr Whitelock said some commentators interpreted her comments as being "right on the line".

Harry's mother Diana, Princess of Wales, was criticised shortly before she died in 1997 over her appeared support for a campaign for a worldwide ban on landmines launched by Britain's Labour Party - a stand that infuriated Conservative politicians.

"Diana was at times seen to be promoting herself perhaps to the detriment of the royal family and that's what Meghan is going to have to navigate," Dr Whitelock said.

"The challenge for Megan is her whole career has been about self promotion, and I guess trying to make it in Hollywood and as an actress is about self promotion.

"So the challenge is not to push yourself forward beyond the brand that is the royal family.

"You can be very visible and popular but it's very important that it's done within the confines of the royal family."

Before her engagement to Harry became public last November, Meghan had a popular lifestyle blog, The Tig, which aimed to inspire women and "reframe the beauty content to include think pieces about self-empowerment".

That's been since shut down, along with Meghan's Twitter and Instagram accounts.

However, some of the more pointed political comments she's made in the past before she met Harry have been dragged up by the media, like when she called Donald Trump "divisive" and "misogynistic" during his campaign to become US president.

As a royal those type of comments will have to be kept within the confines of palace walls.

Royal commentator Richard Fitzwilliams expects Meghan will continue to speak out about issues she feels strongly about.

But she'lll have Harry to guide her through the maze of royal protocols, much in the same way William guided Catherine as she took on public duties after their 2011 wedding.

"She will learn that, so no selfies, no autographs, the order of precedence within the royal family - all of that," Mr Fitzwilliams said.

"It's a different world being a member of the royal family."

Comparisons to Catherine will probably also be inevitable.

But Meghan will have more freedom than Catherine, who is expected to become Queen Consort when William ascends the throne.

"I think she will perhaps unfairly be compared to Kate," Dr Whitelock said.

"But of course they have particular paths laid out for them because when Prince Charles inherits the throne William will be the heir and Prince of Wales, he will be next in line."

Meghan's main role will be to support Harry, with royal watchers expecting them to team up for public appearances like they did for Anzac Day ceremonies in London last month.

"There's no doubt Kensington Palace will be carefully going through all the requests for her to be patron for charities and working out what role she'll want," Dr Whitelock said.

"Even before Harry she was already becoming a kind of spokesperson on lots of issues as well as being an actress and I think she's going to want to continue that.

"I think the royal family are going to see that's a good thing, her speaking out on relevant issues, but she's going to be coached and counselled about what are the causes that will be particularly important to her."

Despite the big learning curve ahead, Meghan is determined not to let her new role change her.

"Nothing about me changed. I'm still the same person that I am, and I've never defined myself by my relationship," she insisted in a groundbreaking interview published in Vanity Fair last September.