Prince William has sparked rumours of a reunion between him and Prince Harry next year!

On Sunday, the future king , where they handed out the first prizes for William's landmark project.

During the event, which saw finalists and winners present solutions to some of the world's biggest environmental challenges, the Duke of Cambridge took to the stage to make a big announcement.

"Now, I hope you agree, that London and the UK has put on quite a show for our first year," he told the crowd of scientists, activists, celebrities and more.

"So, for the second year, we need to pass the baton to a country whose leadership is essential for all five of our Earthshots."

And where, exactly, does plan to host the awards next year?

"Where better than the nation that inspired the Moonshot all those years ago?" he continued, referencing a project pioneered by former US President John F. Kennedy.

"I'm delighted to announce that The Earthshot Prize will be heading to the United States of America in 2022."

The announcement sent royal watchers into a frenzy, as taking the awards to the US could mean a reunion for William and brother Harry.

After stepping down as senior royals in 2020, moved to California, USA, where they currently reside with their two young children.

The couple have kept a relatively low profile in the States and have kept their son, Archie, and , out of the public eye.

But with William set to jet to the US for the second Earthshot Prize Awards next year, there is speculation that the Duke and Duchess of Sussex will be invited.

They may even be invited to speak or present an award at the event, though no details have been revealed yet.

It would be one of the Sussexes' first joint 'royal' engagements since leaving the royal family.

Harry has returned to the UK twice to attend royal engagements; first for 2021, then for the unveiling of a , in July.

Now it looks like the royals, or at least William and Kate, could soon cross the pond to visit .

The Cambridges may also choose to bring their three children – , Princess Charlotte, and Prince Louis - to the US, as they did when they travelled to France for James Middleton's wedding.

That could mean a reunion for them and cousin Archie, as well as a first meeting with Lilibet, who was born after the Sussexes' royal split and has never been to the UK.

There have been rumours Recently, there have been rumours that Harry and Meghan were planning to return to the UK for Lilibet's christening.

However a spokesperson put the talk to bed with a statement to , saying: "Plans for the baby's christening have not been finalised and as such, any assumptions about what will or will not take place are mere speculation".