They were asked after sending Jessica's Tree, Thornton's web series about suicide, to Heads Together, the mental health campaign co-ordinated by Princes William and Harry and their wives, Kate and Meghan.
"They watched it and absolutely loved it," said Thornton.
She and Mora have a meeting at Buckingham Palace on Monday and another at Kensington Palace — home to multiple royals, including William and Kate — the following day.
Details of who will attend are scant. Thornton, 24, hopes to meet the royals but will be happy just to brainstorm ways to boost mental health with key figures from the campaign.
"Everyone knows that we've got the highest youth suicide rate by capita and I don't think the solution just lies within New Zealand," said Thornton. "We have to be brave enough to go out and ask for help from other countries."
• Watch the episodes of 'Jessica's Tree' below:
Heads Together was launched in 2016 by the Royal Foundation of the Duke and Duchess of Cambridge, William and Kate, and Duke and Duchess of Sussex, Harry and Meghan.
The campaign brought together eight charity partners to build on their work tackling stigma and changing the conversation on mental health.
"It's working so that they're all working for the same cause," said Thornton.
"Here in New Zealand we've got about 30 helplines that we slap at the bottom of a news article and there's so many politics and [different groups] don't talk and I think it's one of the biggest reasons why our system is struggling so much."
Thornton and Mora were among mental health advocates who met Harry and Meghan in Wellington last October.
Prince Harry and Meghan met Genevieve Mora and Jazz Thornton (second and third left) from Voices of Hope in Wellington last year. Photo / Mark Mitchell
The royals listened intently as they talked about their work with Voices of Hope, using video and powerful, personal stories to show there's a way forward from even the darkest times.
About 60 per cent of the Kiwi duo's followers on social media are domestic, the rest concentrated in the United States, Australia and Britain.
The goal is to grow it into a global organisation, making hope-filled content for every creative stream.
After multiple visits to the States, this will be their first trip to London. They'll also visit mental health advocates to promote their work and host screenings of Jessica's Tree.
Directed and fronted by Thornton, the five-part series examines why her friend Jess took her life in 2015 and what her suicide can teach us.
Telling the story of Jessica, in Jessica's Tree, has saved lives and made many people think about mental health. Photo / Supplied
Contending that no one is born suicidal, it was made with the participation of Jess' family and friends.
"The whole series is about helping people understand what it is to be suicidal and then what you can do to help," said Thornton when it was released via nzherald.co.nz last month. "I don't want people to watch this and 20 minutes later move on with their lives. I don't think you can watch this and not change the way that you think."
The response has been "amazing but overwhelming", Thornton said yesterday. "You should see my inbox. It's ridiculous. I've had thousands of messages from people who said they watched it and chose not to take their lives, or people saying that they finally understand mental health.
"It was hard making it, but every individual life that has been saved as a result — totally worth it. Jess would be ecstatic to know that her story is not only changing lives here in New Zealand but is going global. She'd be amazed."
