Prince William will spend four days in Cape Town (Image: Getty)

Prince William is preparing for his first major overseas trip since his wife’s cancer diagnosis.

He will spend four days in Cape Town for Earthshot Week, his global environmental prize that has become a critical project for the heir to the throne.

Just like his father, William has put climate change at the heart of what he does and his ambitious 10-year project aims to find and scale innovative solutions to pressing environmental challenges.

Earthshot is set to be the Prince’s defining project, just as the King’s Trust (formerly the Prince’s Trust) is for Charles and the Duke of Edinburgh Award was for the late Prince Philip.

The annual prize hopes to encourage people to come up with evidence-based solutions or projects under five categories: Protect and restore nature, Clean our air, Revive our oceans, Build a waste-free world and Fix our climate.

Earthshot has fast become a highly coveted award, with major companies such as British Airways, Uber, Microsoft, Deloitte and IKEA supporting William’s ambition.

It is highly respected and has been lauded by Sir David Attenborough, who sits on the judging panel, Australian conservationist Robert Irwin and actress Cate Blanchett.

This year William is hoping to capture the hearts and minds of young people – with Earthshot CEO Hannah Jones saying the Awards Ceremony on Wednesday has been masterminded to appeal to Gen-Z.

Over the course of his four-day trip, the prince has a number of events with young people as he attempts to inspire them to put their time and talent to fixing the planet.

But as well as showcasing his beloved Earthshot prize, William’s visit to Cape Town marks another reassuring sign in his wife’s recovery.

Kate revealed in September that she completed her course of chemotherapy and will start to ease herself back into public duties.

Princess Kate joined her husband in Southport last month (Image: Getty)

She is expected to attend the Cenotaph on Remembrance Sunday and last month the princess conducted her first in-person engagement since last December as she joined William in Southport to meet the families of the three young girls who were killed in July’s horror stabbing.

The prince has travelled abroad on a handful of occasions since the Princess of Wales’ diagnosis at the start of the year, attending D-Day commemorations in France and heading to Germany to support England in the Euros, but this marks his most significant overseas trip of the year.

Family has always come first for William and spending time with his wife and three children has been incredibly important this year as they all came to terms with Kate’s diagnosis.

But as Kate’s health improved the heir has ramped up his work schedule and his upcoming trip to Cape Town is a testament to her continued recovery.