Heidi Klum ’s in a hairy situation -- literally -- polling fans to see if chest fluff is normal, or if she’s the only Angel sporting a peach-fuzz bra.

Okay, so the German supermodel doesn't exactly have a full-on chest carpet -- just a lone rebel strand sprouting from one boob ... which she proudly flaunted on IG, giving it a playful tug for the camera.

Heidi zoomed in -- while speaking German -- enough to reveal the spout was gray, and while she played it cool, she polled fans on whether this was normal ... or just her own follicle freak show.

But looks like Heidi's little chest whisker sparked more buzz than she bargained for ... 'cause by the time we looked, she had the comments shut down.

This ain’t Heidi’s first hairy tale though -- back in Feb she copped to boob hair as long as

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