Country star Blake Shelton's father passed away last year (12) after begging doctors to take him off life support because he was in too much pain to continue his lung cancer fight.

Richard Shelton lost his battle with the disease on 17 January, 2012, prompting the Honey Bee hitmaker to cancel a number of upcoming concerts as he struggled to overcome his grief, and now the singer has opened up about his dad's final moments, admitting it was difficult to watch him take his last breath.

He tells Men's Journal, "I remember him laying there in the bed, and he really couldn't even talk... It got to the point where he was choking to death. One day the doctor came in, and dad said, 'Can you make me go to sleep and not wake up?' So they took him off the ventilator and gave him some morphine for pain. They said it could be a couple of days. But he went to sleep and died in, like, three or four hours."

Shelton also reveals he received a message from his late parent from beyond the grave after stumbling upon a lost letter Richard wrote to his son when he turned 17.

He explains, "It was, like, five pages thick. The first couple lines said, 'Hey, I didn't get a chance to tell you some things that I wanted to tell you about entering the world...' There was also a lot of s**t about how to treat people, how to get respect, how to look people in the eye, and how to shake their hand - basically, how to be a man in the world.

"It was like I was having a conversation with him I never had."