The news comes after Toronto head coach Ryan Nelsen stated that the MLS outfit faced stiff competition for Defoe's signature, claiming that "top-four" Premier League clubs were also interested in acquiring his services.
"I think if you ask any Premier League club then they would take Jermain right now," Nelsen said.
"I know Tottenham are getting offers from everywhere for his services at the moment, from top-four clubs in England as well."
However, Toronto have won the race to sign the 31-year-old and he will join the club on February 28.
Defoe stated that he will give his all for the north London club until he leaves next month.
"Everybody knows how much this club means to me. I will play my heart out for the team and the fans until my last kick for the club," the striker said.
"I have had a fantastic time here and the fans have always been amazing to me.
"I am grateful for the opportunity for myself and my family to experience living overseas and for me to play in the MLS with a contract that will take me to the age of 35."
Following the announcement, Tottenham boss Tim Sherwood spoke of Defoe's new challenge. He said: "This is a great opportunity for Jermain and he feels it is one that he wishes to pursue."
Tottenham confirmed the news on their official Twitter account.