Supported by Action For Addiction for which the Duchess is a patron, the project was launched in April 2013, when Kate and comedian John Bishop visited Willows Primary School in Wythenshawe, Manchester.
July's visit to Blessed Sacrament school in the London borough of Islington will include meeting project staff and the school's head teacher. The Duchess will later sit in on a counselling session.
The Duchess of Cambridge in 2014
The project helps children who have been affected by parental addiction. John will once again attend the visit with Kate, and the pair will listen to speeches towards the end of the trip.
During her Manchester visit last year, Kate spoke of her desire to help children in need.
"Last year I asked The Royal Foundation, which I share with William and Harry, what could be done to help these children in partnership with our foundation, Comic Relief work, to explore this issue," said Kate during a three-minute address.
The Duchess holds a number of charitable patronages, many of which complement the three key areas that The Royal Foundation of The Duke and Duchess of Cambridge and Prince Harry, established in 2009, aim to make their focus.
The Duchess of Cambridge launches the project in 2013
These include The Art Room, The National Portrait Gallery in London, and East Anglia’s Children’s Hospices, for which she released a touching message in support of Children's Hospice Week.
The doting mum recently visited one of their centres where she met seriously ill youngsters and learned about how volunteers contributed to the day-to-day running of the facilities.
"Around the clock support is crucial for children receiving palliative care," said Kate. "They and their families often need help every hour of every day, both in hospices and at home.