Alex charmed legions of ITV viewers as he appeared on This Morning with his mother. Picture: YouTube.com

London - His first reaction was shock … then sheer delight. This is the moment five-month-old Alex Denman-Sang heard for the first time.

Sitting on his father Paul’s lap, he broke into a heart-melting grin as his mother Jen called his name.

Alex had been born deaf but was fitted with cochlear implants at Alder Hey Children’s Hospital in Liverpool last month.

Denman filmed his reaction as he heard his first sounds. She is heard saying, "Hi, it’s mummy", as Alex smiles at her and giggles. 

She quips: "God help us when we get home to your brother." The footage went viral after it was posted on Twitter by the hospital, and has been viewed more than 830 000 times. 

Alex charmed legions of ITV viewers as he appeared on This Morning with his mother, sitting happily with presenters Rylan Clark-Neal and Gok Wan. Denman told how she and Mr Sang found out about his deafness in the days following his birth.

Doctors carried out a series of tests and diagnosed sensorineural hearing loss in both ears. Plans were made for him to be fitted with the implants. Alex, who was nicknamed Fidget in the womb because he was never still, is taking time to get used to them. 

"He takes them out and chews them. He chews everything," Denman said. She told This Morning of her shock when her video went viral. At the time, Alder Hey said the family were "overwhelmed" and "genuinely surprised" by the response. She said: "It was only meant for family and friends. It just went crazy."