Shaw has penned a new five-year contract with the club.
"I'm very pleased to have finally signed it," Shaw told his club's official website last night.
"I committed myself back in January, and I'm glad everything has been sorted out.
"I've been getting a lot of questions about my future, but all of the Saints fans will have known that I committed my future in January.
"I've been here since I was eight and I've loved every single moment of it. I want to stay at this club, and signing this contract means I'm here for another five years."