She is due to be welcomed by staff, patients and the Lord Mayor of Portsmouth, Councillor Terry Hall.
The Princess is due to tour the hospital, visiting the paediatric and critical care departments, meeting staff and patients.
She is also unveiling a commemorative plaque in the hospital's education centre in front of hospital staff and guests, including Mick Lyons, organiser of the Rocky Appeal.
The Princess' first engagement of the day will be to open Defence Science and Technology Laboratory's new facilites at Portsdown West, in Fareham.
She will attend a Trafalgar Night Dinner onboard HMS Victory, at Portsmouth's Naval Base and will also visit HMS Sultan in Gosport.
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