04/01/2016 2:11 PM AEDT | Updated 15/07/2016 12:51 PM AEST

'A Beautiful, Brave Young Man': Teenage One Punch Victim Cole Miller Dead

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The father of a teenage victim of an alleged one punch assault in Brisbane's nightclub district described him as "a beautiful, brave young man".

Elite water polo player Cole Miller, 18, was allegedly randomly assaulted while walking with a friend in Brisbane's Fortitude Valley on Sunday morning.

His father Steven confirmed he died in hospital on Monday in an emotional press conference thanking hospital staff, police and the water polo community.

"He struggled bravely in the intensive care unit of the Royal Brisbane Hospital and our family and many close friends have been at his bedside since the incident,” Miller said.

“Cole was a beautiful, brave young man with his whole life yet to be lived.”

Two men, both aged 21, have been charged with grievous bodily harm.

Police on Monday said evidence would be reviewed, indicating the duo's charges could be upgraded at their next court appearance in February. One man is from Coombabah and the other from Tanah Merah.

Both have been remanded in custody.

Detective Senior Sergeant Tom Armitt told reporters on Sunday the victim and a friend were walking in the area when they were approached by four men.

"A short exchange has occurred and the victim was struck once to the back of the head, has fallen forward," he said.

"This is a random act of violence. There is no indication the victim knew who the offenders were."