Which is what I already said.We can sit here and think up how they knew eachother all day. I can't say for sure, but I doubt DC had things thought out this far ahead that early in the comic.
Maybe that's because she doesn't think Llewellyn is "a big scary thing" who's going to eat them.Thankfully, there wasn't much interaction between them to make us think any different.
...looking back, maybe he did!
Point 1: Millie's mom isn't even surprised by him.
http://www.ozyandmillie.org/1998/om19980930.html
