Four-year-old twins Sean and Emma have been honoured with special bravery medals after their quick-thinking saved their grandmother's life.
Their actions allowed medics to reach Ruth Clarke, who had suffered a seizure or an electrical malfunction in the brain.
Ruth said the swift actions of the four-year-olds ensured she received prompt medical attention.
The twins' proud mother, May O Suilleabhain, said she cannot believe how courageously they responded to the emergency.
"We thought the absolute worst," she said. "We thought that nanny had passed away.
"Sean was on the phone to me. He was screaming that he couldn't wake nanny up.
"Our first thought was that she had passed away, and what do we do now?
"The twins were locked in their home with their nan and it was dark outside."
"What do they do? It was unbelievable how they reacted. We are so, so proud of them."
The twins received the special bravery medals at the Naionra (play school) of Gaelscoil Mhichil Ui Choileain in Clonakilty, Co Cork, where they are students.
The twins were being looked after in their own home by Ruth and their grandfather, Stephen, while their parents, May and Brian O Suilleabhain, were in Kerry for the day.
When Stephen returned home, Ruth was left on her own with the twins. When Ruth suddenly lost consciousness, the twins tried to wake her up, but she did not respond.
Sean displayed remarkable quick-thinking by finding his grandmother's phone and searching through her stored numbers. He was then able to ring both his mother and his grandfather.
Sean was able to contact his mother, who immediately raised the alarm, while his grandfather raced to the house.
Sean and Emma were able to unlock the door to allow him in to assist their grandmother.
Paramedics were on the scene within minutes - and their prompt intervention ensured Ruth could be saved.
Emma had assisted Sean throughout the dramatic incident.
Their grandmother was rushed by ambulance to hospital and, thanks to the rapid attention she received due to the twins raising the alarm, has since made a good recovery.
Stephen said the twins' swift actions were truly remarkable.
"I got a phone call from Sean at 6am. Ruth was babysitting at the house because Brian and May were at a concert in Tralee."
"They said they couldn't wake nanny. I rushed over to the house and found my wife unconscious on the bed.
"Sean had also phoned his mum who had phoned for the ambulance.
"The ambulance arrived and they rushed her to Cork University Hospital where she was in a coma.
She was in a coma in the Intensive Care Unit (ICU) for two days.
"They later put it down to epilepsy or an electrical malfunction in the brain.
"She is OK now - but they saved her life. No doubt about it.
"When I arrived at the house I couldn't get in because the door was locked.
"I said to Sean to open the door and, when he couldn't reach the latch, he got his tricycle, pulled it to the front door, climbed up on it and managed to open the door. He is only four but he is a very, very bright child.
"I didn't know what to expect that day. It was a terrible ordeal because you just didn't know what the outcome was going to be."
The twins' father, Brian, said he was very proud of Sean and Emma.
"I was wondering if everything was OK and what was happening when I saw the call coming through on nanny's phone," he said.
"We realised what the story was after Sean calmed down on the phone and told us exactly what happened. We rushed home straight away.
"Sean plays games on the phone and his nanny was teaching him how to use it. So he was well used to using the handset.
"We are delighted he was able to use the phone and ring both his grandad and ourselves.
"We are delighted with the two children and they are thrilled by the award here today."
Tributes to the children were paid by emergency services.
"Their quick actions definitely saved her life that day," one paramedic said.
The twins' parents and grandparents admitted they were "very, very proud" to see the little boy and girl honoured for their actions.
Tributes were paid to the bravery and quick-thinking of the twins by the Gaelscoil Principal Cionnaith O'Suilleabhain, West Cork Rapid Response director Dr Jason van dear Velde and the Mayor of Clonakilty Gretta O'Donovan.