The Scottish champions rejected three bids from Norwich for their top scorer, who has 23 goals so far this season.
Reports on deadline day claimed fourth and fifth offers had been tabled by the Canaries in an attempt to test Celtic's resolve.
However, the Hoops were determined to hold onto one of their key players ahead of their Champions League last-16 meeting with Juventus.
Celtic boss Neil Lennon even took to his official Twitter account on Thursday night to clarify the situation, as the transfer deadline edged closer.
He tweeted: "Contrary to reports there have been no fresh bids for Gary and even if there are they will be rejected..he is NOT for sale."