Pharmacy worker Debbie King, 23, went to the hospital for a routine 20-week scan and was startled to notice a face on the side of unborn baby girl's head - a face, which she adds, bears an uncanny resemblance to her grandmother.
King, from Galway, Ireland, said you can see the mysterious face in the ultrasound if you tilt your head to the righty.
"It wasn't until my friend said she could see a face that I looked at the scan properly," she said.
"As soon as I did I could see it was nanny. It's not like you've even got to squint."
King said she then showed the scan to a few other people, who agreed it looks liked her late grandmother.
She said: "They thought it was the strangest thing that they have ever seen in their whole lives."
King's grandmother, Teresa King, died in February 2012 aged 82, after battling dementia for two years.
The dressmaker was married to husband Eddie for 30 years and had four children and six grandchildren.
Teresa King would now be a great-grandmother to three children and the fourth, King's little girl, on the way.
Debbie King, who became pregnant in September and is due any day now, said: "I used to talk to her [Teresa King] about everything.
"I still ask her things in my head and this has made me realise she's listening.
"It feels like she is watching over us. It has made me feel a lot more at ease during the pregnancy."
Debbie King's sister, Amanda King, 25, said: "When I looked at the picture the hairs on the back of my neck stood up. It was the creepiest thing I have ever seen.
"Obviously when someone really close to you passes away, you look for signs of them everywhere and we were wondering if that's what we were doing.
"But everyone agreed that the family resemblance is uncanny.
"Me and Debbie are strong believers that no one is ever really gone and we feel like nanny is in her final resting place now.
"She's letting us know that she's there and she's happy."
Mum-of-one Amanda said she believes it is a sign that everything will go smoothly with King's pregnancy and described her nan as a "guardian angel".
She said: "She was such a wonderful nanny who doted on her grandchildren. She always spoiled us and she loved babies.
"I had my son seven years ago and she absolutely loved him because he was her first great grandchild.
"Since she passed away, my brother has had two kids and she would have loved to meet them.
"Debbie fell pregnant in September and she has always been worried about the pregnancy, because this is her first child.
"This is her way of reassuring us and making sure this baby arrives safe and sound.
"We have a guardian angel minding our new arrival and feel blessed to know nanny is watching."