Before ya guzzle down a bunch of holiday treats over the next few days, here's Cristiano Ronaldo reminding folks what's possible with a ton of discipline and living in the gym.
The 40-year-old international soccer star went to social media to show off his Greek god-like bod on Friday ... telling his 105 MILLION X followers he just hopped out the sauna -- and, lucky for us, providing visual proof.

The Al Nassr striker rocked nothing but black briefs and slides for the photo op .