The 42-year-old actor - who played Hodor until Season Six of the HBO fantasy drama when the character was killed off - has complained about the impact of famous faces appearing on the programme.
Speaking to The Huffington Post, he said: ''I'm not a fan of the cameos in 'Game of Thrones.' I don't like them. I think it's stupid. I don't mind going on the record on that. I just think it takes you right out of the world. Especially Ed Sheeran. I was like, 'Why is Ed Sheeran here?' I mean, Ed Sheeran's great. He's a great guy, great musician, but why is he in 'Game of Thrones?' ''
Although the 'A-Team' singer's cameo - in which he played a Lannister soldier and sang a song to Arya Stark (Maisie Williams) - came after Nairn had left, it's still rubbed him the wrong way.
He ranted: ''I'm not saying I'm not a fan of Ed Sheeran. I'm being tactful here, but just not a fan of the cameo. I think most people would agree with me there. It was a big snap to reality.
''It's like, 'What? What?'... It's a fantasy show. We're all caught in this amazing world and spend so much time and money and talent to create, and all of a sudden there's a pop star? What?''
The programme - which is based on George R. R. Martin's 'A Song of Ice and Fire' novel series - has had a number of cameos over the years, including the likes of metal group Mastodon.
While Nairn doesn't like these moments as a rule, he did admit to enjoying Sigur Rós' appearance at Joffrey's wedding in season four.
He explained: ''[Sigur Rós] kind of got away with it because they're so quirky ... They're almost like 'Game of Thrones' world in real life.
''They're so elven and spiritual. I think that works, but apart from that -- I mean, I understand why people want to be in it, but just no. Go away.''
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