Cristiano Ronaldo Models New Undies

Here's Cristiano Ronaldo ... putting his man junk front and center in a modeling shoot for his brand new underwear collection ... and he couldn't be more proud.

The soccer superstar just released his 6th collection of his CR7 undie line -- and shocker, he decided to tap himself as the main model.

So, why is Cristiano so fond of his man panties?

"Underwear is the first thing you put on in the morning, so it’s the foundation to feeling your best. I always feel good when I’m wearing great underwear -- it’s a confidence boost."

Just to be clear ... the wealthiest, most ripped, model-banging, soccer champion in the world needs a "confidence boost" from his boxer briefs. Huh.

Just click on the photos already.