Well-wishers lined the streets to get a glimpse of the Royal couple as they visited Anglesey and Swansea on Tuesday in their first appearance in the country in their new roles as Prince and Princess of Wales.
The Princess' comments came during a discussion with volunteers and members of the congregation at St Thomas Church in Swansea about the importance of community services.
During the last two years the church has been transformed into a community hub, and includes a food bank, facilities for homeless people, and a not-for-profit café and community training kitchen.
It is also home to the Swansea Baby Basics baby bank, a volunteer-led project that distributes essentials to vulnerable mothers and their newborn babies across the city.
Princess Catherine said: "With the cost of living crisis, there are a lot of desperate people out there." She added that the food bank was a "lifeline to so many people" particularly after the pandemic and amid the soaring cost of living.
"There is amazing work going on here. Keep up the hard work."
Pat Hughes, one of the women who runs the food bank, said: "It was lovely to chat with the Princess and it's something we won't forget."
The Prince and Princess also spoke to Leah Rees, 30, and Francesca Cardone, 44, who have both been community nursery nurses in Swansea for the past seven years.
They work with parents who may not be prepared for a baby, and refer them for support at the baby bank, which prepares any items they may need, such as baby baths and clothing.
Before visiting Swansea, the pair started their day by arriving at RNLI Holyhead Lifeboat Station where they met crew, volunteers, and people who have been helped by the charity.
The Prince and Princess, who used to live in Anglesey, walked from the lifeboat station to the Holyhead Marine and Café Bar where they met locals including representatives of small businesses and organisations including the Coastguard and Sea Cadets.