The two men are late additions to the festival speakers programme, which also features award-winning British foreign correspondent Christina Lamb, Otaki poet and GP Glen Colquhoun, art commentator Hamish Keith and Minister for Arts, Culture and Heritage, Christopher Finlayson.
Festival resident artists Simon Kaan, Areta Wilkinson, Michel Tuffery and Martin Hill are also included in the speakers' programme.
Mr Bolger will talk at the Infinity Crystal on Saturday, May 2 at 1.30pm about New Zealand and its position in the world after global economic meltdown.
He entered politics in 1972 and represented the King Country until he retired in 1998.
Three days after being sworn in as prime minister in 1990, Mr Bolger's government was forced to bail out the Bank of New Zealand. His government introduced MMP, settled three major treaty claims and introduced a New Zealand honours system.
Ousted by Jenny Shipley in a 1997 coup, Mr Bolger was subsequently appointed ambassador to the United States.
He is now chairman of NZ Post and Kiwibank, chairs several other companies and in 2007 was elected chancellor of Waikato University.
Mr Fergusson will speak after Mr Bolger at 3pm about the relationship between New Zealand and the United Kingdom in the 21st century.
He first came to New Zealand as a 7-year-old and says the relationship has been part of his life for as long as he can remember.
