The actor - who admitted he thought he was "going to die" after a surfing stunt went wrong on the set of his new movie 'Chasing Mavericks' during which he was engulfed by two enormous waves - said the accident reminded him of when he saved a child from drowning in Scotland fourteen years ago.
He told US chat show host Kelly Ripa on 'Live With Kelly and Michael' on Tuesday (23.10.12) that the uncontrollable heaving sounds that came from his body while he recovered were similar to those that erupted from the small boy he rescued from the River Tay in 1997.
The 42-year-old star - who was briefly hospitalised after his accident - was handed a certificate of bravery by the Royal Humane Society of Scotland in 1997 after putting his own life at risk to pull a child from the river.
But the '300' star brushed off his bravery and admitted he was so shocked by the incident that he struggled to carry the young victim back to his hotel.
He said: "I tried to take him up hill but my legs were like jelly from the adrenalin and everybody's watching me and I couldn't make it up the hill."
Speaking previously about the rescue, he also played down his heroism. He said: "I didn't feel like a hero at all.
"I was initially gripped by fear and an empty feeling, thinking that the boy was dead."
Footage of Gerard's accident, which happened during filming in California last December, was shown to the public for the first time on ABC's 'Good Morning America' this week.
He said: "It looked like a tsunami coming in. I was down. I just didn't come back up, really. I just started to think, 'Wow, I'm going to die making a movie.'"