Bar Refaeli: There's a Baby In Here ... I Swear

A shot of Bar Refaeli looking smokin' in a bikini isn't unusual, usually ... but in this pic she is, unbelievably, 5 months pregnant!

Looking less bloated than most people after a footlong sub -- the supermodel posed in full profile to show off her baby bump ... which is really more pimple-like than anything.

Sunbathing Bar's caption? "My girl craved some Vitamin D."

We wanna see mom craving some double cheeseburgers! Check out Bar from 6 months ago when she was NOT prego ... not much difference.

She and Coco have all the luck.