Game of Thrones star Charles Dance's secret family history

Actor Charles Dance. Photo / Getty

Game of Thrones star Charles Dance has wept on screen after discovering he had two secret sisters born almost 50 years before him.

The British actor choked up as he learned the devastating story of his biological sisters on BBC show Who Do You Think You Are? as it unearthed his heritage.

"It's rather extraordinary to know that here in my 70th year, I am only finding out about all of this now," he said. "There is something about this that I do find quite moving."

During the show, Dance found out his father, Walter Dance, had a daughter, Norah, born in 1898.

An emotional Dance said: "I have a sister, I see, right. I have to say this is quite moving, because I know so little. So gradually, bit by bit, we are finding out about the life of a man who I just knew by his name WD."

He also discovered that his second half-sister, Mary, was born in 1903 but killed at five after being hit by a scaffolding pole.

"It is overwhelmingly sad and I don't think, as a parent, that one would ever get over something like that," he said.

However, in a moment of levity, Dance also found out his father was a hero in the Boer War, serving during the most brutal guerilla phase of the battle.

Walter Dance was awarded a campaign medal after being involved in a "physical and psychologically demanding" hunt for saboteurs.

"It's rather extraordinary to know that here in my 70th year, I am only finding out about all of this now," said Dance, who is best known for playing Tywin Lannister in HBO's Game of Thrones.