"It's been a complicated transfer because of the situation with MK Dons and Plymouth but we are very pleased to have secured him," said Saints manager Alan Pardew.
"He is a bit of a maverick footballer and I think the side could do with a bit of individual flair which he brings."
Puncheon, who was not signed in time for Saturday afternoon's visit of Stockport, added: "I jumped at the chance to come here and I can't wait to get started."
Source: Team Talk
Source: Team Talk