The Prince of Wales has said his children "will definitely be exposed" to homelessness as he prepares to launch a new project on the issue.

In a Sunday Times interview, Prince William revealed he wanted them to know "some of us need a helping hand".

The prince said he has been thinking about the right time to take them to a homeless shelter, like his mother Princess Diana did with him aged 11.

He is set to launch a new five-year project tackling the issue this month.

The interview comes as a new portrait of the Prince pictured smiling with his three children has been released by Kensington Palace to mark Father's Day.

In his first newspaper interview as Prince of Wales, he told the Sunday Times he had spoken to his children, Prince George, Prince Louis and Princess Charlotte, during the school run about people they could see sitting outside supermarkets.

He said: "When I left this morning, one of the things I was thinking was when is the right time to bring George or Charlotte or Louis to a homeless organisation?'

"I think when I can balance it with their schooling, they will definitely be exposed to it. On the school run, we talk about what we see.

"When we were in London, driving backwards and forwards, we regularly used to see people sitting outside supermarkets and we'd talk about it.

"I'd say to the children, 'Why are they there? What's going on?' I think it's in all our interests, it's the right thing to do, to expose the children, at the right stage in the right dialogue, so they have an understanding," he explained.

"They [will] grow up knowing that actually, do you know what, some of us are very fortunate, some of us need a little bit of a helping hand, some of us need to do a bit more where we can to help others improve their lives."

The prince would be following in the footsteps of his mother, Diana, Princess of Wales, who took him and his brother in 1993 to visit a London homeless shelter run by the Passage, an organisation of which he is now the patron.

Earlier this year he recalled the experience and said: "My mother introduced me to the cause of homelessness from quite a young age, and I'm really glad she did.

"I think she would be disappointed that we are still no further on, in terms of tackling homelessness and preventing it, than when she was interested and involved in it."

Later this month the prince will launch "a really big project" from his and his wife's charity, the Royal Foundation. He is hoping it will provide "living conditions up and down the country that improve people's lives who need that first rung of the ladder".

It will be a new advocacy for the prince who primarily campaigned and spoken up on the issue of mental health in recent years.

He says he is particularly concerned about youth homelessness, and part of his project will be about preventing that. The number of 16 to 24-year-olds homeless or at risk of homelessness was 122,000, according to Centrepoint's freedom of information requests to councils.

"For me, 122,000 is a figure that's way too high," he said. "We need to get ahead of the curve to stop this becoming more and more fixed."

The prince also revealed when asked there are "absolutely" plans for social housing on the Duchy of Cornwall - the estate given to the heir of the throne, which provides him with an income.

The royal spoke to the newspaper after opening a homelessness-charity project for young people in work or apprenticeships who need help finding affordable housing.

Prince William, who is also patron of homeless charity Centrepoint, previously made headlines sleeping rough in Blackfriars, London, for one night to highlight the plight of homelessness.

He has also donned the red tabard worn by Big Issue vendors to sell the magazines in the capital.