Leave it to coke to make a sugary ad featuring smiling babies. The credit for the song (or blame, depending on your mood) goes to writer Jesse Ridder and performed by Huib Koch, both of Ogilvy Amsterdam.
Fun fact-- after consulting with our in-house mum at Adland, I was reminded the first time a baby actually smiles is when it shits itself. However, the advertising mum is sappy and the giggling babies worked on her. So clearly Coke knows its target market.

Client: Coke Agency: Ogilvy and Mather Amsterdam Writer/Performer of song: Jesse Ridder (writer) Huib Koch (performer)