Classis good overcalling situation?

[Mathieu]

Tough spot as I think BTN has AT. Not sure but I am thinking he would have bet/folded a weaker made hand on the turn and would have folded A hi on this river. It's possible that he chickened out and that now he feels compelled to call the bluffer with something like A8 or A7.

If you are not sure wether the button would bet/fold a weaker made hand on this turn, then calling the river is OK getting over 6.5-1.