Iain Armitage mourns 'extraordinary grandfather'

Young Sheldon star Iain Armitage has shared the heartbreaking loss of his beloved grandfather, Richard L Armitage.

"I am heartbroken to share with you that my extraordinary grandfather died on Sunday. He was my hero and I adored him," wrote Armitage.

His grandfather would have turned 80 later this month.

Armitage went on to detail how his grandpa served in the Vietnam War and was father to eight children and grandfather to 13.

"I don't even know how to begin to tell you about my grandfather, but one of his most significant achievements was helping to save the lives of over 30,000 people when evacuating South Vietnam in 1973," wrote Armitage.

He also shared that his grandfather loved basketball and the United States Naval Academy and "somewhat unexpectedly" became a fan of Taylor Swift.

"I think he knew everything. I am endlessly proud to be his grandson, and I'm glad he knew it. I already miss your terrible jokes and I will miss and love you forever, Dad A," the actor concluded.

The elder Armitage served as deputy to Secretary of State Colin Powell during President George W Bush's first term.

His widow, Laura, told the Washington Post that the cause of death was pulmonary embolism.