Coronavirus lockdown is "stressful" for many people and it is important to look after mental health, the Duke and Duchess of Cambridge have said.
Prince William said there was an "ever-increasing need" for people to know where to access help and support.
In a BBC interview, he said NHS workers often had to absorb the pain and loneliness of coronavirus patients.
The duke went on to reveal how anxious he was when his father, the Prince of Wales, was diagnosed with the virus.
In a wide-ranging interview about the pandemic, mental health and the NHS, Prince William described how the three-week lockdown had been "frustrating" for many people and "pressure, stress and isolation" had been building up.
"If we are going to go forward with more time spent in lockdown, then there is going to be an ever-increasing need for people to look after their mental health and take it seriously and also know where to go to get the support they might need," he said.
Catherine said there had been a focus on physical well-being during the lockdown - with people being told one of the reason they can leave their homes is for one form of exercise a day.
"While that's hugely important we mustn't forget our mental well-being as well and making sure you're reaching out to those people around you that you have access to - even if it's over the phone or online to really make sure you have those conversations," she said.
Prince William said there was a concern people might think they were "not worthy of support" because of the pressure on services during the coronavirus pandemic.
"It's important that other people aren't forgotten and those who do need help, and do need support, and haven't necessarily ever had to think about their mental well-being, start to do that in this weird climate we're in," he said.
The couple want to encourage people to talk to each other using technology and also use online tools such as NHS Every Mind Matters to help them during the coronavirus pandemic.
During the interview, the duke and duchess also praised NHS workers and said they were making the nation proud with their "stoicism and determination" to get through the pandemic.
But Prince William said some staff were understandably anxious and it was important not to alienate those who "worry" and "are scared going to work every single day".
He said NHS workers often have to absorb the pain and loneliness of coronavirus patients and "take it home to their families".
"We're not superhuman, any of us. So to be able to manage those emotions and that feeling is going to take some time after all this is over as well."
After four weeks of lockdown William and Catherine are banging the drum for mental health, telling potential sufferers to talk and reach out, and trying to be upbeat royals at a time when much the rest of the Royal Family is, by necessity or choice, out of sight.
The curtain drawn over Royal private life is pulled back a bit: there are videocalls between the generations, there are ups and downs, Mum is clearly a bit frazzled by the whole thing, Dad is thinking about his bod. It is rather like a lot of British lives, albeit with more palaces.
William and Catherine have spent a fair bit of time talking to hospital workers over the past few weeks and it is clear from their tone that it has affected and alarmed them. They are sounding the alert now for mental health assistance for those at the sharpest end of this crisis.
The duchess added: "What we're seeing now is the NHS and the frontline workers doing the most extraordinary job. And that's really come to the forefront in the last few weeks.
"It's going to dramatically change how we all value and see our frontline workers. That is one of the main positives you can take from this."
Prince William also spoke about how he felt anxious for his father Prince Charles when he tested positive for coronavirus after having mild symptoms.
"I have to admit, at first I was quite concerned, he fits the profile of somebody, at the age he is at, which is fairly risky," said Prince William.
But he said his father had experienced many chest infections and colds, so he felt optimistic Prince Charles would recover.
He also said he worried about his grandparents - the Queen and the Duke of Edinburgh - but they were doing everything they could to ensure they were protected and isolated.
The duchess said they had faced "ups and downs" during the lockdown "like lots of families".
She said homeschooling their children - Prince George, Princess Charlotte and Prince Louis - had been "challenging" but they had a kept a strict regime.
"We don't tell the children we've actually kept going through the holidays. I feel very mean," she added.
The couple also said they have been keeping in touch with other family members through online video calls.
"It gets a bit hectic, I'm not going to lie, with a two-year-old you have to take the phone away," Catherine said.
"It's quite hectic for them all to say the right thing at the right time without pressing the wrong buttons. But it's great and it's nice to keep in touch with everybody."
- Public Health England's Every Mind Matters platform has launched new advice, focussed on looking after people's mental wellbeing during the coronavirus pandemic.
- For information on organisations that can offer mental health support you can also visit the BBC Advice pages.