Mike Tyson may be 53 and 15 years retired, but in many respects he has never been in better shape.
The former undisputed heavyweight world champion recently announced he will return to the ring in four-round exhibition bouts.
But his return to fitness has been a long journey after the American ballooned to almost 30 stone a decade ago.
He had since adopted a vegan diet and recently took on renowned mixed martial arts trainer Rafael Cordeiro as his new coach.
And if recent training footage wasn't enough to convince the world Tyson is in tip-top shape, Cordeiro confirmed it.
He toldÂ ESPNÂ : "As soon as we started training I said â€˜My Lord'. I didnâ€™t know what to expect from a guy who hasnâ€™t hit mitts for â€“ I think â€“ almost ten years.
"So I didnâ€™t expect to see what I saw â€“ I saw a guy with the same speed, the same power as a guy who is 21, 22-years-old.
"And I can tell; you would have to be a good guy to spar with Mike, because if you donâ€™t prepare, he is going to drop you for sure â€“ 100 per cent.
"The power is different level. I have trained a lot of heavyweights in my career, with not a lot of respect for everybody, but he is almost as powerful as Wanderlei Silva is right now.
"When you talk about power, I held his right hook and thought â€˜he is going to kill somebodyâ€™."
â€œWhen I hold mitts, I like to hold them close to my face and the first time, I saw his right hook and I saw my whole life [flash before me].
"My wife, my daughters, my dog â€“ I see everything because I thought, â€˜Iâ€™m going to die hereâ€™.
"But itâ€™s just the fear; every time I hold mitts for him and he threw any kind of combination, it would push me off of the mat.
"He puts on pressure, pressure, pressure. Mike Tysonâ€™s game, as everybody knows, is pressure. Same way he fights, is the same way he trains."
Tyson struggled to adapt to a life without boxing after his defeat by Kevin McBride in 2005.
His weight shot up to 27 stone as he battled drink and drug problems - but he would eventually restore his health by ditching meat and embarking on a strict exercise routine.
He also began to rack up business interest, starring in a one-man show on Broadway before launching his own cannabis ranch.