The 31-year-old new mother took her youngster to a local supermarket in Oahu, Hawaii with her boyfriend Norman Kali.
The new parents looked the picture of happiness as they strolled around with their baby son wrapped in a cream and white printed blanket.
The opening season featured 14 regular speaking roles, making it the largest cast in American prime time television when it premiered.
Before it was decided that Jack would live, Kate was to emerge as the leader of the survivors; she was originally conceived to be more like the character of Rose.
Dominic Monaghan auditioned for the role of Sawyer, who at the time was supposed to be a suit-wearing city con man.
'What I wanted originally was six kids,' she told Ocean Drive magazine in January.
These two had such a weird breakup, and now we may know why.