The 39-year-old made an emotional return to Sunderland in January, and made seven League One appearances, before making the ‘really tough decision’ to bring an end to his playing days in March.
After 22 years in the game, Defoe said it was the right time to bow out, yet the former England striker has clearly kept himself in good shape to prolong his career.
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At the end of the video, Kane asked how old his former international team-mate was, to which Defoe replied: “39 H, 39, so literally just finished."
Defoe then added: “Literally now, I could still play now."
“Obviously you still get the niggles and like my ankles and my back and all that sort of stuff but I still feel,…it wasn't a case where I’m training and I can’t get my shots off, shots are getting blocked and that.
"The lads were still saying to me 'JD, how are you this sharp at 39', because like you, I’ve looked after myself from day one.”
Sunderland’s sporting director Kristjaan Speakman spoke about Defoe’s decision to retire following the club’s promotion from League One.
“Jermain came to that conversation full of optimism on what he felt he could come and provide," Speakman said.
"The environment in the changing room is one of the components in the changing room that has got us over the line and what you don’t want in that type of scenario is people who are not committed.
“If you look round, I was really confident of the play-offs because I could see a group of individuals that had the bit between their teeth and they wanted to be the group that got Sunderland back into the Championship.
“I don’t think within that, you can have people that are bit-parts. I think Jermain made a really tough decision that he felt that he couldn’t continue. It’s not ideal because naturally you lose a player out of your squad and whether that is through injury or something else then that can create an issue.”