The Daily Mail says the Polish international's contract, which runs until 2011, is believed to be worth around £30,000-per-week.
The agreement protects Celtic's right to a sizeable fee should they decide to sell Boruc at any point over the next couple of years - with Poland's Euro 2008 participation a forthcoming showcase for his talents.
"I am so happy to have signed the new contract because Celtic have been good for me," said Boruc last night. "I never really wanted to leave. It was not my hope to play elsewhere at the moment and I would not have wanted to leave Glasgow under these circumstances.
"The negotiations over my new deal were long and difficult so everyone is happy that we have managed to reach agreement.