Robin Gibb's son has opened up about the star's tragic death, calling his passing "peaceful and dignified" and revealing it wasn't cancer that killed his father.

The Bee Gees star was in remission from colon and liver cancer at the time of his death last Sunday, and his son Robin-John has now explained the music legend suffered kidney and liver failure in his final days.

He also reveals he was with his dad until the end, along with his mother Dwina and his siblings.

Robin-John tells the Sunday Express, "The end was peaceful and dignified, there were no theatrics. It was only later that I cried and cried... It wasn't the cancer that killed my father; those reports are wrong. Dad had actually gone into remission and the cancer was completely unrecognizable, it was too small to detect. No scan could see it. He actually died of kidney failure."

He goes on to explain that Gibb was battling back from a bout of pneumonia which left him in a coma when he suffered a seizure, which led to a sharp decline in his health: "Three days before (he died), he was sitting up and watching DVDs and then suddenly he had a seizure. He was then dosed with sedatives to deal with the side effects of his chemotherapy and his liver just couldn't process them. He deteriorated to the point where it started to affect his kidneys as well. Basically my father died of kidney and liver failure. It was a really sudden downturn."

Robin-John adds, "I was sitting next to his bed with my mother and we saw that his heart had started to give out. We knew it was the end. We called my brother and sister and they came in. I was cradling his head and holding his right hand, and my mother was holding his left. I gave him a kiss... We watched him go and told him we loved him."