Gelder who played Kevan Lannister in the fantasy drama has passed away, five months after being diagnosed with bile duct cancer.
The British actor played the character who was the younger brother of Lord Tywin played by Charles Dance, for the first season of the drama. Gelder later reprised his role in the latter series of the HBO series, before being killed off in the final episode.
Along with Game of Thrones, Gelder also starred as Mr Dekker in Torchwood: Children of Earth, and guest starred in His Dark Materials as librarian scholar Charlie, and Zellin in Doctor Who.
Ian Gelder's death was confirmed by his long term partner and actor Ben Daniels, who shared this message on Instagram.
Describing Gelder as his "absolute rock", Daniels wrote, "It is with huge huge sadness and a heavy heart broken into a million pieces that I'm leaving this post to announce the passing of my darling husband and life partner Ian Gelder".
"Ian was diagnosed with bile duct cancer in December and yesterday he passed at 1.07pm", he revealed. "I’d stopped all work to be his carer but neither of us had any idea that it would all be so fast".
Daniels continued, "If we weren’t together we spoke to each other everyday".
"He was the kindest, most generous spirited and loving human being. He was a wonderful wonderful actor and everyone who worked with him was touched by his heart and light", he added. "I honestly don’t know what I’ll do without him by my side".
"He coped with his dreadful illness with such bravery, with no self pity. Ever".
"He was remarkable and will be so missed".
Ian Gelder also featured in TV shows, London's Burning, Agatha Christie's Poirot, along with several productions in London's West End, and Shakespeare's Globe Theatre.
