Prince William has opened up about having the 'hardest year in my life' following his wife and father's cancer diagnoses.

In a remarkably candid - and at times emotional - interview at the end of his official visit to South Africa he admitted the past few months had been 'brutal'.

But the prince also said how hugely 'proud' he was of Catherine and the King for handling their health battles with such dignity and bravery.

He added that the Princess of Wales was now 'doing well'.

Speaking in Cape Town yesterday, the future king covered everything from his much-discussed beard - which apparently had his daughter, Princess Charlotte, in floods of tears when she first saw it - to his passion for 'meaningful' royal work such as his landmark Earthshot Prize environmental awards.

But it is was his response to how the past year had been for him as a husband, father and son that will move people most.

Slightly sighing and lowering his voice, he said: 'Honestly? It's been dreadful. It's probably been the hardest year in my life. So, trying to get through everything else and keep everything on track has been really difficult.

'But I'm so proud of my wife, I'm proud of my father, for handling the things that they have done.

'But from a personal family point of view, it's been, yeah, it's been brutal.'

Asked how is the princess is 'getting on', he smiled and said: 'She's doing well. Doing well.'

William added of his relaxed demeanour in Cape Town this week: 'It's interesting you say that, because I couldn't be less relaxed this year, so it's very interesting you're all seeing that.'

Earlier this week he praised Kate, who was diagnosed with an undisclosed form of cancer in February and underwent a course of 'preventative chemotherapy', as having 'been amazing this whole year'.

She recently revealed that she has finished her chemotherapy treatment. 

His father, King Charles, was diagnosed with cancer following routine prostate surgery in January - although the two are not said to be connected - and is still undergoing weekly treatment but has pleased doctors with his progress.

William, 42, made clear that he intends to continue to plough a different furrow when it comes to his royal role and duties than that of this father and grandmother, for the time being at least.

He admitted that he doesn't necessarily like the extra responsibility that comes with his still relatively new role as Prince of Wales, but admits that it has given him the time and freedom to build huge global initiatives such as the Earthshot Prize and the chance to afford 'meaningful' change.

'You mention the added responsibility and the freedom in the same sentence,' he laughed.

'It's a tricky one. Do I like more responsibility? No.

'Do I like the freedom that I can build something like Earthshot then yes.

'And that's the future for me. It's very important with my role and my platform, that I'm doing something for good. That I'm helping people's lives and I'm doing something that is genuinely meaningful.'

William was speaking at a 'seaweed innovator showcase' where he picked up a pair of earrings made from 'beach cast kelp' to take home for his wife.

He sported a a blue blazer that he had sourced from a local vintage store in London as part of his effort to wear as many recycled or sustainable items of clothing as possible during the week.

He says what many people don't realise - or even want to realise - is how much work it takes behind the scenes to bring such a massive global initiative together outside of the day-to-day public engagements he is seen on.

'So, the Earthshot is a culmination if you like of all that put together. But it takes a lot of work, and there's a lot of unseen stuff that goes on, a lot of meetings, a lot of people coming in, a lot of chatting and phone calls, letters, all trying to sort of make the Earthshot get to being the best possible entity it can be,' he said.

The prince's 'green Oscars' were born out of his frustration at the 'global pessimism' around climate change and the environmental crisis.

He decided the best way to combat this was to help develop the most inspirational solutions to the biggest problems facing mankind.

Every year for a decade five winners will each receive a £1 million in prize money and mentoring to scale up their ideas.

This year's entrants have included everything from a firm making trainers from biodegradable material to a new technology capturing waste heat and turning it into electricity.

William admitted he can get frustrated at the slowness of getting people on board but feels that at last, four years in, he's finally seeing results.

'I'd like it to be more a team sport,' he said.

'And so, when you go and approach people...business...or even government...and say, listen, we're building this incredible thing. Please come on board. Some people are extremely fast and keen to it. Others take a little bit longer and it's those people who take a little bit longer, I'm like, guys, we just don't have the time.

'So, yes, I get a bit frustrated that it takes a long time to convince people that this is worthy of their attention. But I guess that's the nature of a global environment prize you do, you start from scratch and it's going to take a bit of time.'

But added that he was 'really pleased' with the progress they had made so far and was 'really thrilled' with Wednesday's live-streamed awards ceremony.

For the first time they have taken place in Africa, a continent with which he has a special bond having retreated there following the death of his mother, Princess Diana, and later proposed to his wife.

William admitted he felt 'emotional' about it, saying he felt particularly affected hearing the Disney Lion King anthem ' Circle of Life' being sung by an African choir to open the ceremony.

'Hearing the Circle of Life. I don't know about everyone else, but hearing the Lion King and things like that gets me quite emotional,' he admitted.

'So, when they started singing and I saw the clips from the top of Table Mountain and we were all there and it's happened. I did feel quite emotional.'

He said he wanted to translate the 'impact' of such an amazing ceremony into raising the visibility of the solutions that it is showcasing.

'So you guys have seen for yourselves the scale of the solutions. I mean, they cover all sectors in all walks of life. Brilliant people, some barely started, some been a bit more established and have a bit more money. But overall all doing fantastic work in the same direction,' he said.

'I think the key thing for us is how do we translate that into more impact, more scale, and ultimately, greater progress in tackling environmental challenges.'

And the prince said companies - and countries - all needed to do more.

He said: 'I definitely think so. We're giving this amazing platform to all of them. And really it's an amazing platform for business to come in and poach what they want.

'But if we keep waiting....we're going to keep eating into time that we just don't have.

'And so my message to business really is: hurry up and be courageous. Invest faster because we just don't have that time.'

The prince said he wasn't sure yet whether his children had been able to watch the ceremony on YouTube as he hadn't 'clocked in with them yet' but said he hoped they did.

He will be reunited with them at home on Friday before being back on duty this weekend alongside his family at a number of Remembrance events.