GERARD Butler has revealed he once saved a drowning teenager. 

During a recent appearance on Late Night with Seth Meyers, the Paisley-born actor said he's saved "a couple of human beings", including one 13-year-old boy he found struggling in the River Tay. 

The Olympus Has Fallen star says he had taken his mum to a hotel near the river where he stayed when he was filming his first movie.

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He said: "When I just started acting, the place that I filmed my first movie, it was a beautiful place with this River Tay in Scotland but it is cold and it has a lot of undercurrents. 

"But it was a beautiful summer's day and I said to my Mum, 'let's go where I stayed, this hotel that I stayed at'. 

"And we're both just lying there and we fall asleep and suddenly I hear this screaming. 

"And I wake up, I say to the woman next to me, 'is there somebody in trouble?'"

Butler says he then walked over a hill and saw a boy in the middle of the river and claims he did "the worst rescue attempt".

He continued: "There is this boy in the middle of the river and he disappears underwater and then he comes back up and he looks dead to me. 

"And all I could think was 'I wish I was a heavier sleeper'. 

"Cause I'm like, I know I'm going to go in there but I just wish I hadn't woken up. 

"And I did. I've got courage but I'm clumsy as hell. 

"I did probably the worst rescue attempt. 

"So, I swim out and then I grab him but I didn't go back so I was kind of holding his head underwater. 

"And his eyes were wide open and we got him back."

Butler explained once he got the boy to shore, another person gave him the Heimlich manoeuvre and he regained consciousness. 

He says he got an award for bravery from the British Humane Society for the incident and he stayed in touch with the boy over the years, and even made a video for his recent wedding. 

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The actor also revealed on the episode he accidentally rubbed his face with phosphoric acid while shooting the movie Plane and felt like he was "burning alive". 

Butler says the incident happened when he was filming a scene where he had to pretend to fix his character's plane. 

He said: "I'm sticking my hand in between these two wheels, kind of pretending that I know what I'm doing.

"Every time I bring my hands out, they're covered in blood and green fluid, right?

"And I'm like, 'I don't know what this green fluid is.'"

He continued: "I'm rubbing my face, and suddenly, it's in my throat, it's in my mouth, it's up my nose, it's in my eyes. 

"It's burning my face, and I mean burning."

He says he then discovered the green fluid was "essentially phosphoric acid".

He added: "I'm just, like, burning alive.

"So, it was intense. It actually burned for hours."