I was quite surprised to find out she has one.
It says 'let it be' on her right ankle.
I promise to be on the lookout for a better picture of it :)
Something she said back when she was 18:
“I mean, obviously I don’t have anything against it, because look at my boyfriend,” Hilary said while dating Joel Madden. “But I think I would just get so bored with it, looking at the same thing over and over again. And [Joel's] found a simple solution to that — he just keeps adding more and more and more. But I don’t think I could. I don’t like that pain.”