A heartwarming video has emerged from the US of a baby hearing his mum's voice for the first time.

The video, shot earlier this month in Gwinnett County, Georgia, shows eight-month-old Xander, adorably giggling when he hears her mum's voice using a Phonax hearing device.

''Xander suffered a brain bleed while he was in NICU when he was nine weeks early. They told me he passed his hearing screen while he was in NICU,'' her mum later wrote online.

''When he was discharged after 59 days in the hospital, I noticed he didn't get startled like other babies.''

''It took me 3 months of advocating for my son for them to test his hearing. They thought I was just being a over protective mother. I was proven right. Never underestimate a mother!,'' she continued.

''His hearing will not get worse but he also will never get better without his hearing aids,'' she added.

++CLIENTS PLEASE NOTE: THIS VIDEO HAS BEEN EDITED++