The global star will take to the stage for an open air concert at Castle Ward, in Co Down. The performance is set to take place on Sunday 26 May as part of the three day festival at the 18th-century mansion.
It's part of a finale of weekend festivities in the Strangford Lough 'Lough Lively' celebration.
Belfast man Van's latest studio offering, in a career spanning five decades, is new album Born To Sing:No Plan B.
Van Morrison said: "This is my first concert at a National Trust property in Northern Ireland, and what better place to perform than the shores of Strangford Lough? The beautiful surroundings of Castle Ward should make it an extra special night and I'm really looking forward to being back in County Down."
Barbara Muhly, Property Manager for Castle Ward, said: "We are thrilled to welcome Van Morrison back to County Down and incredibly excited to host him at Castle Ward. He is an iconic performer and it will make for a special summer evening to have him perform at one of Northern Ireland's most beautiful places.
"He can be sure of a very warm welcome, and we might even give him some of our special Castle Ward honey to help prepare his voice for the gig! Visitors can also be sure of a great evening on the lawns of this incredibly special place. What more could you ask for to start your summer?"