A baby born with a rare hearing deformity was able to hear for the first time — and gave an unexpected reaction. 

Nellie Rosales, an 11-month-old, was born with an ear deformity, which resulted in deafness in one ear. 

The baby, from Fayetteville, North Carolina, has atresia, which is the absence or underdevelopment of the ear canal and middle ear structures.

BABY HEARING MOM'S VIOCE FOR THE FIRST TIME CAPTURED IN EMOTIONAL VIDEO

She also has microtia, which is normally accompanied by atresia — meaning an ear deformity from birth which causes the ears to appear different, according to Texas Children’s Hospital, according to SWNS.

The baby was recently fitted for a hearing solution and then heard her dad Jacob’s voice for the first time — which greatly upset her. (SEE the video at the top of this article.)

Jacob Rosales is the 28-year-old dad of little Nellie; he told SWNS that seeing her hear him for the first time took his breath away. 

BABY ERUPTS IN LAUGHTER AFTER HEARING CLEARLY FOR FIRST TIME

"It brought sunshine to my heart, even if she was overwhelmed," he said. 

In the video above, Nellie Rosales can be seen getting fitted for the device — and then shortly after hearing her father, burst into tears.

VIDEO OF MOM SEEING BABY HEAR FOR THE FIRST TIME GOES VIRAL

The device allows her ear canal to be bypassed via a transmitted sound using vibrations from her skull, as SWNS reported.

Today, Jacob Rosales said his young daughter is loving her device — and that the difference in her hearing is "night and day."

"The difference is clear — she can hear things from other rooms, and she understands what we say, too," he said to SWNS. 

Nellie Rosales now hears the dogs outside the house — and will stop to turn her head. 

Jacob Rosales and his wife Sharon Hernandez are both members of the military — and are grateful for the health insurance that helped them provide the device to their daughter. 

"The insurance we have is great, and the device costs $6,000," he said. 

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"If we didn’t have the insurance, we would have had to take out a huge loan for the device."

Jacob Rosales told SWNS that as she’s grown a bit, she gets excited to put on her hearing device. 

"She gets very excited to put it on," he said of his growing daughter.