The Duke and Duchess of Cambridge make big announcement on Twitter as they launch new project

Prince William and Catherine sent social media into a frenzy when they dropped a huge hint that a big announcement was imminent late on Monday night.

The Duke and Duchess shared a video via their official Kensington Palace Twitter account looking back at the highlights of 2019 and wrote, “To all the fantastic organisations and inspirational people we met and worked with in 2019: Thank you for a wonderful year, and see you in 2020!”

But their statement didn’t end there, as they followed it with, “Stay tuned for our first announcement of 2020 very shortly,” alongside an emoji of the world.

Naturally their 1.8 million followers have been busy trying to guess what the announcement could be, with most people thinking a foreign tour could be on the cards for the family in 2020.

One eagle-eyed fan wrote, “Given the [world] symbol they used perhaps some international tours are coming in 2020?”

Another said, “The choice of globe emoji is interesting (Africa).”

And they didn't have to wait long as on New Year's Eve, the couple announced The Earthshot Prize - a decade of action to "repair the earth" and help "solve earth's greatest problems".

On their new project, The Duke of Cambridge said, "The earth is at a tipping point and we face a stark choice: either we continue as we are and irreparably damage our planet or we remember our unique power as human beings and our continual ability to lead, innovate and problem-solve.

"People can achieve great things. The next ten years present us with one of our greatest tests - a decade of action to repair the Earth."

It comes just days after Royal Expert, Omid Scobie, said 2020 was set to be a big year for the Cambridge family.

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Speaking on The HeirPod podcast, he revealed, “Next year is going to be busy for the Cambridges. Expect royal announcements over the holidays, which I think is a slight break away from tradition.

"There was a briefing at Kensington Palace just this week where they gave us a number of new announcements that will be coming out over the holiday period."

And what could these announcements include?

"We will be hearing about a new initiative from Prince William and some other news as well," he said.

The family made their most recent outing on Christmas Day when Prince George and Princess Charlotte arrived at St Mary Magdalene Church on the Sandringham estate in Norfolk.

READ MORE: WHY THE DUCHESS OF YORK SPENT CHRISTMAS ALONE

The Cambridge family also went for a traditional Christmas lunch at Buckingham Palace before Christmas with the likes of Mike and Zara Tindall.

Opening up about the chaotic event on his House of Rugby podcast, he explained, "The family lunch - there must be about 70 of us there – there are seven tables and the kiddies have their own little one in a different room."

Talk about a house full!