“Game of Thrones” star Ian Gelder has died at the age of 74

Ian Gelder, who played Kevan Lannister Game of Thrones, has died. He was 74.

Gelder’s death was announced by his husband, Ben Daniels, in a post on Instagram on Tuesday, May 7.

“It is with great sadness and a heavy heart that I leave this post to announce the death of my beloved husband and life partner Ian Gelder. Ian was diagnosed with bile duct cancer in December and passed away yesterday. “By 1:07 p.m. I had stopped all work to care for him, but neither of us had any idea it would all happen so quickly,” Daniels wrote.

Daniels remembered his partner of over 30 years as his “absolute rock” and “the kindest, most generous and loving person.”

“When we weren’t together, we talked every day,” he added, noting that Gelder was also a “wonderful, wonderful actor and everyone who worked with him was touched by his heart and his light.”

“I honestly don’t know what I’ll do without him by my side. He dealt with his terrible illness with so much bravery and without self-pity. Never. He was remarkable and will be greatly missed,” Daniels continued.

He made the announcement alongside a photo of the two at Christmas, which he shared after Gelder was released from hospital and experienced “the worst three weeks.”

Gelder’s agent also confirmed his death to PEOPLE, remembering him as “a beautiful man, a fine actor” and someone who “will be greatly missed by his colleagues and all who loved him.”

DMA Management added in a post on Xformerly Twitter that “the world will be a smaller place without him.”

According to his IMDb page, Gelder appeared in 12 episodes of game of Thrones and had many other notable credits including Doctor Who, Fifteen-LoveAnd Its dark materials.

Never miss a story — sign up for PEOPLE’s free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

Gelder was next scheduled to appear in the upcoming season as a vampire named Santiago Interview with the vampirePremiering Sunday, May 12, on AMC and Prime Video The Lord of the Rings: The Rings of Power Season 2 premieres later this year.