Hollywood superstar Will Smith has admitted he had no idea of the risks of brain injury his son might have suffered from playing American football.

Smith plays a neuropathologist who made the first discovery of a football-related brain trauma in his new film Concussion.

He said he felt a responsibility to inform parents of the hazards because he was not aware of the risks to his own son Jaden.

I felt as a parent I was uninformed, so I wanted to create this for people to make informed decisions

The actor, who first found fame as The Fresh Prince of Bel-Air before making films such as Independence Day, Men In Black and Bad Boys, takes on the role of the real-life Nigerian-born doctor who was the first to publish findings of chronic traumatic encephalopathy in American football players.

Will Smith admitted he had no idea of the risks of brain injury his son Jaden might have suffered from playing American football.

Speaking on the red carpet at the world premiere of the film at AFI Fest in Los Angeles, Smith said at first he was unsure about taking on the role.

“I love football, I’m a football dad, I grew up with the Philadelphia Eagles and there is nothing better than that Sunday afternoon, so when I met Dr Bennet Omalu and I had him walk me through the science it became almost a burden. I felt like I had to deliver the information because I’m a football dad and I did not know, I did not know when I watched my son play football in high school for those four years, I did not know there was a potential long-term neurological issue.

“I didn’t know the potential results of repetitive head trauma and I felt as a parent I was uninformed, so I wanted to create this for people to make informed decisions.”

Concussion is being released in UK cinemas on January 29.