Video: Meet the Northern Ireland singing doc who's hitting all the right notes with young patients
He's a doctor with a difference - as you might hear him before you see him.
Meet Dr Ryan Coetzee, who works on the children's ward in the Causeway Hospital, Coleraine.
He has become a sensation after a video of him wowing his young patients with his singing voice and lighting up the ward with joy and laughter was shared online.
It was Portstewart mum Olivia McLaughlin who shared the video of him singing to her son Oscar (8).
The 29-year-old doctor from South Africa has been involved in music from a young age - and says that him singing to his patients is nothing new, but he is flattered at the response he has got.
But ultimately, he uses his singing as a distraction method for the children, and if it raises a smile from them, that's the most important thing.
He was inspired to get into medicine after watching the classic film Patch Adams.
The 1998 film is the true story of the heroic Hunter 'Patch' Adams, who is determined to become a medical doctor because he enjoys helping people - and does this using humour and pathos.
"I watched that when I was six or seven-years-old, I loved it, and being silly and crazy and laughing, and it was quite an inspiring movie.
"And then my aunt, I'm very close to her, she's a nurse as well. So she led me in that direction and then I kind of stuck to it," he added.
Music has always come naturally to Dr Ryan and he says it fits in perfectly with his work.
"I started off singing when I was nervous, but I always just sing naturally and casually go around doing it.
"But the first time it was noticed was with the patients back in South Africa when I was still a student.
"I'd sing around with them, I'd hold hands with them and we'd walk down the ward and sing our songs, all our little African songs."
Hospitals are a daunting place for most people, and Dr Ryan knows that it can be especially traumatic for children, so he does his best to take their mind off it - and his methods help their parents, too.
He explained: "There is nothing more precious than a child's laughter or a child smiling at you.
"And it's really beautiful to see, especially in a miserable environment where doctors have to come and put up drips and take bloods, and it's unfortunately something we have to do to treat the patients.
"But you can distract them as much as you can, make them laugh and get a smile afterwards.
"There is nothing more precious than seeing that."
Dr Ryan said he is "really flattered" by the response to his singing, but he also just loves singing. He joked that his friends back in South Africa weren't shocked when they saw the video as they knew it was what he's always done.
"I really enjoy it.
"It's kind of my natural thing. A few of the comments from friends back in South Africa are, 'This is exactly who he is, I'm not shocked'."
Dr Ryan has only been working in the children's ward for the past three months and says that wherever he goes, his colleagues are usually a little shocked at first, but then they end up requesting songs for children throughout the ward.
He laughed: "The Bare Necessities has been my go-to for the past few weeks, but everyone is a bit sick of Bare Necessities now, so I need to change it up."
For eight-year-old Oscar, it was a special moment when he met Dr Ryan. He was admitted to the Causeway Children's Ward last week.
The youngster was born with a number of conditions including severe combined immune deficiency which is, in essence, being born without an immune system.
And when he was seven-months-old it was discovered that he had developed lymphedema, which is a rare condition in children. It had initially developed in one leg but then spread to both.
He had a bone marrow transplant when he was aged nine in Newcastle and has been in and out of hospital here.
His visits hadn't been as frequent until last week when he started complaining of pain in his leg.
His mum Olivia took him to the Causeway Hospital as he developed a rash and had a temperature.
"I went straight to A&E and they were very good. We are only 20 minutes from the hospital and by the time we got there it had spread, he started vomiting and was springing a temperature and got a bit delirious.
"But we were quickly seen in A&E and then transferred up to the children's ward, that's when we first met the singing Dr Ryan, he admitted us onto the ward."
Oscar was then diagnosed with cellulitis which is difficult to treat in lymphedema, so he had to stay in for seven days.
One morning when he woke up, he told his mum he had heard someone singing George Ezra's hit Shotgun - and then he realised he could still hear it, and it was actually Dr Ryan, the singing doctor.
Olivia said: "They came round for the ward round and I said to Ryan, 'You'll have to come back and sing to this boy because he heard you singing this morning.'"
Olivia posted the video of him singing to her son on Twitter and she says it all went "crazy".
"People were contacting me and saying they had seen the video.
"When we were in the first night he was a lovely doctor to deal with and very good with Oscar.
"I was chatting to the nurses and they said he constantly sings to anyone, it's just so great."
Olivia said it's a great distraction for the kids who are in hospital - and great for the parents to see their children smiling.
"To me it is just a distraction, and he's got a beautiful voice."
He also sang for Olivia's daughter Alice (6).
"I said, 'Would you like him to sing you a song?' and she said, 'No because I'm not a patient.'
"I said, 'He'll sing you a song' and he came in and he sang a song to her, it was Let It Go and the Bare Necessities.
"Just everyone in the ward raves about him, it's so uplifting.
"For a parent it's lovely to see the smile on Oscar's face when he comes in to sing - it's just lovely."
Dr Ryan was also a hit with baby Heidi. She is only 15-weeks-old and always has smiles for him.
Mum Ursula from Cookstown said: "She just loves him. When she was at the peak of her sickness, he got a smile from her. You hear the laughing, the singing on the ward and it takes away from the fact the children are sick."