A 21-year-old student has been hailed a hero after diving into a Donegal river to save a drowning woman who was trapped in a car.

Andrew Johnston was forced to dive underwater four times to free Loreta McKinlay after her car left the road near Lifford on Saturday.

Andrew said he was originally planning on heading to Longitude in Dublin for the weekend – but sold his ticket to take his girlfriend on a trip to the seaside town of Buncrana for a special weekend away.

On Newstalk Breakfast, he said he “had never seen anything like it my life” when he happened upon the accident on his way to the town.

“There was a guy standing on the other side of the bridge and all he said to me was ‘can you swim?’” he said.

“When someone says that you kind of get a gist of what is happening; there was someone in the water - or there was something in the water - that needed to be recovered.

“So I jumped straight out of the car and ran straight for the water and I have never seen anything like it.”

He did not hesitate after the man, Loreta’s husband Philip McKinlay who was covered in blood, told him his wife was stuck in the car.

“I took a breath and went down and I actually had to take my breath again because I couldn’t get enough the first time,” he said.

“I pulled the passenger door open - obviously the water was resisting me opening the door but I was able to get it open with enough force.

“I went down and tried to get into the car and opened my eyes but I couldn’t see a thing - the water was that dirty and that dark, I may as well have has my eyes closed.”

Andrew eventually resurfaced, desperate and empty handed, after realising that the woman was not in the passenger seat.

After checking the driver seat, he struggled - alongside Mr McKinlay - to get the back-door open and eventually pull the unconscious Mrs McKinlay out of the wreckage.

“When we got her, the first thing we did was hold her head above water,” said Andrew.

“I was holding her head up and he was clearing her airways and giving her mouth to mouth while I was giving her chest compressions.

“I didn’t really know what I was doing in truth but I just kind of had to do something.

“I was holding her up above water and he was trying to do that while most of her body was under water.”

Eventually an onlooker threw out a garden hose to the struggling group and they were able to pull themselves in towards the river bank.

With the help of some passers-by, they were able to pull themselves out of the water and to safety.

Andrew left the scene after paramedics arrived and tended to Mrs McKinlay.

He came forward after being hailed a "mystery hero" for his actions in saving her life.

You can listen back to the whole story on Newstalk Breakfast here: