Princess Anne is due to fly in to visit two organisations in Brighton and Hove today (Monday 5 March).
The royal visit coincides with the start of a fundraising campaign by the CAB which is staffed almost entirely by volunteers.
The bureau, which is one of the longest-serving charities in the area, needs a six-figure sum every year just to keep going.
In 2010-11 staff and volunteers advised nearly 7,000 clients on 20,000 problems.
Staff say that they are expecting their caseload to rise as a growing number of people struggle with welfare reforms and rising unemployment.
Edlira Alku, director of the Brighton and Hove CAB, will show Princess Anne around the bureau’s offices at Hove Town Hall in Tisbury Road.
The royal visitor is patron of the National Association of Citizens Advice Bureaux. She will meet caseworkers and volunteers and one of the many people to have been helped by the local bureau.
Among those she meets will be staff specialising in money advice and those working in the HIV Project which has been providing advice to HIV clients for 16 years.
The princess will also visit the Sussex Eye Hospital in Eastern Road, Brighton, to mark its 180th anniversary.
The hospital is run by Brighton and Sussex University Hospitals NHS Trust, which also runs the Royal Sussex County Hospital and the Royal Alexandra Children’s Hospital.
It has been on its present site in Kemp Town since the early 1930s.