"Goodbye Belfast. Goodbye Arya. Goodbye 'Game of Thrones'. What a joy I've had. Here's to the adventures to come #lastwomanstanding #barely #immasleepforthenextfouryears #justkiddingidontsleep," Williams wrote.
The actor also shared a photograph - of a red-spattered white sneakers - which was a befitting tribute to the show famous for its gory and gruesome moments.
Williams' co-star Emilia Clarke also said her goodbyes to the show last month.
"GOT" has been shot in locations such as Northern Ireland, Croatia, Iceland, Morocco, Spain and Malta, among others.
The eighth and final season of the show will air next year.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)