Baby Elijah Cook smiled when he heard his mother's voice for the first time when he was fitted with his very first pair of hearing aids – aged just nine weeks.

The touching moment was uploaded by Elijah's mother, Ahavah, on to YouTube and has since become a viral sensation clocking up more than a million views.

Elijah Cook was born on 2 January 2015 and failed all his newborn hearing tests. After this he was referred to a special developmental and rehabilitation program at Children's Hospital in Minneapolis. After consultation with audiologist, Lori Johnson, Elijah was fitted with his hearings aids on 5 March.

Elijah's mother said the first time she saw Elijah react was incredibly emotional and that her biggest concern was to make sure she didn't cry in front of him as she was so happy.

Since having his hearing aid fitted Elijah has been cooing regularly at his family.