Defoe has been in stunning form for Sunderland this season despite their wretched campaign under David Moyes.
The 34-year-old has netted 14 goals from 30 games and also earned a recall to the England squad last month.
His contract at Sunderland expires in the summer and, with the Black Cats 10 points adrift of safety, a summer departure looks inevitable.
Newcastle want to sign Sunderland star Jermain Defoe
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However, Sunderland's misery could get even worse.
Toon boss Benitez wants firepower to ensure they stay in the top flight and Defoe is on their radar.
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Jermain Defoe infamously left West Ham for Tottenham in 2004
It is said club chief Mike Ashley is open to signing the forward despite the fact he currently plays for their fierce rivals.
Defoe is no stranger to controversial transfers.