As patron of the Hospice, the Duke arrived at 1.45pm on Thursday and
visited the patients before delivering a speech to staff, volunteers, trustees and the Mayor of Eastbourne Mary Pooley.
The Duke of Devonshire said, "I am amazed at the abilities of the staff to cope with the challenges of running a hospice in a Victorian town house.
"Although, the more I see of the staff and their work the more I think they could do it on Mars," said the Duke.
He described the hospice as a 'wonderful place' and one of the 'most highly regarded hospices in the country'.
The Duke said the decision to double its capacity was the right one and he praised the architect for the plans.
Residents also seemed pleased about the new building and were excited to meet the Duke.
Joan Angus, 82, said, "The staff here are very, very kind and I think more people are coming here so it is an excellent idea to make the premises bigger."
Some have expressed a concern about the future of the hospice after this large amount of money has been spent on the re-build.
"The hospice has accumulated money and the future of the hospice is the new build. I believe the future lies in bricks and mortar," said the Duke.
However, an extra £1.5million needs to be raised for the work.
Kara Bishop, chief executive of St Wilfrid's Hospice, said she was grateful for the huge amount of support from the local community but explained it would be complaisant to say the total would be an easy target to meet.
The building work on the Mill Gap Road site is expected to start in June 2009 and continue for 18 months.
A spokesperson from the hospice said there will be no interruption to any of the services provided.