characters Jaime and Cersei Lannister's incestuous relationship has been frowned upon since day one, but even actor Nikolaj Coster-Waldau admits the love affair feels a "bit wrong".
The Danish actor who plays Jaime on the hit TV series, says he and actress Lena Headey are more like actual brother and sister off screen.
Coster-Waldau has spent a lot of time locking lips with Headey - his twin sister on the show - and said the pair now squirm at the sight of a kissing scene.
"Lena Headey is brilliant as Cersei," Coster-Waldau told Red Bulletin.
"We know each other so well now that it feels weird every time when we have to do a kissing scene."
"So as soon as they yell cut we make faces of disgust, not seriously, but it does feel a bit wrong."
The show created a stir in season four when Jamie and Cersei shared a heated moment of passion in front of the corpse of their son.
Game of Thrones season six is due to be released in New Zealand on April 24.