77-Year-Old Golf Legend Gary Player -- I Was Born to Strip Naked for ESPN 'Body Issue'

77-year-old pro golfer Gary Player didn't do a lick of extra training for his naked debut as the oldest man ever in ESPN's "Body Issue" -- dude says he's been in tip-top shape since birth ... aka the '30s ... yeah, he's that old.

Gary tells TMZ, “I did not do anything special for the shoot" ... other than busting his hump working outdoors on his farm in South Africa everyday for a few months prior to dropping trou for ESPN.

He added, "I was already relaxed, tanned and ready to go.”

Before Gary flashed the family jewels for the shoot 2 weeks ago in Miami ... he says ESPN treated him like a king and provided a serious spread of his fav foods -- including crudités, fresh fruit, hummus, salad, and herbal tea. No wonder GP's in great shape.

As for the whole naked thing, Gary says it didn't bother him one bit -- "I was relaxed and confident in my own skin to do this."