Jen Selter's famous ass is going international -- the Instagram phenom just landed her first magazine cover, but TMZ Sports got a few behind the scenes shots.
Jen's butt got tapped for the new issue Forever Sports ... a British-based sports lifestyle mag, which wisely saw the value in a cover girl with Selter's stats -- as in her 6 million IG followers.
The photo shoot went down in Miami, and naturally features several mesmerizing photos of Jen's eyes. Kidding ... it's all about dat ass.
Check em' out.