Sibel Kekilli (Shea), Finn Jones (Ser Loras Tyrell), Ian McElhinney (Ser Barristan Selmy) and Daniel Portman (Podrick Payne) posed for pictures with fans on Tuesday evening, ahead of the sold out event opening on Wednesday.
The exhibition will feature original costumes and props from the series, including the Iron Throne, and 11,000 tickets were snapped up in just two hours of going on sale.
The First Minister and deputy First Minister met members of the Game of Thrones cast and crew, local, national and international media.
Mr Robinson said: "Quite simply Game of Thrones is an amazing show made in spectacular locations across Northern Ireland.
“Its incredible success, its vast size and scale, coupled with Northern Ireland’s expertise and input to the series, is sending out a very strong message about our capabilities in the film and TV industries."
Mr McGuinness added: “To date the show has contributed in the region of £80 million to the local economy and I am pleased the economic benefit will continue through Series 5, which HBO committed to earlier this year."
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