The German supermodel's aunt researched into her family tree and discovered the Klums were very rich and well-connected.
Heidi told the New York Daily News newspaper: "I have a whole history of my family. I had an aunt who really got into it and dug up the family tree.
We used to be very rich and then we got very poor and we sold our title which was von Klum. Over a hundred years ago. They had to sell it. I would have been Baroness von Klum. I could be Baroness von Klum but now I am not."
Despite her privileged background, Heidi recently revealed she finds well-groomed men a turn-off.
Heidi, who is married to British singer Seal, prefers rugged looking men and insists preened chaps don't do anything for her.
The mother-of-three said: "If it looks like they've tried too hard it looks feminine. If you're going to think about it, don't look like you've thought about it."