The royal couple, whose last joint official engagement was in support of London Poppy Day, arrived to the excitement of crowds waiting outside the charity's head office in London.
New mum Kate wrapped up warm in an Orla Kiely bird print, tailored coat which showed off her svelte figure. She completed her elegant look with suede ankle boots and a matching brown clutch bag.
William looked dapper in a navy suit and maroon tie as he escorted his wife into the building.
As the Duke and Duchess toured the central London office, the royal couple met with staff and young people who spoke about the ways Only Connect helps support ex-offenders and young people at risk of re-offending.
The charity, which helps 10,000 people a year, is said to have reduced re-offending by nearly half. Helping former offenders is a cause close to William's heart and his family, as his own aunt Lady Jane Fellowes — the sister of Princess Diana — is one of the trustees of Only Connect.
William and Kate then visited two sister projects at the head office — Bounce Back, which works with prisons, and Handmade Alliance, which trains prisoners in textile making.
Young offenders from Handmade Alliance had prepared a special workshop display of garments and textile decorations which William and Kate admired and praised.
Earlier this month the Duke also visited the St Giles Trust in Camberwell where he met clients, advisors and staff who work with offenders and disadvantaged people to help them rebuild their lives.
Since leaving his military career in September, the future King has filled up his diary with more royal duties. Kate, meanwhile, will carry out a handful of engagements as she focuses on looking after the couple's four-month-old.