I'm sure the answer is out there somewhere but I've yet to find it.
On a Knight's Advance activation, can he attack before (or interrupt) the completion of his movement?
Advance says, "After defeating a monster with an attack using a melee weapon, exhaust this card to move up to your Speed and perform an additional attack."
So, first off, this is not an action. It's tacked onto the end of whatever attack it's triggered on.
Secondly, since it says, "move...and...attack" and not "move...then...attack", I'm inclined to say it can be attack then move, or move then attack. There is a thread here on BGG where apparently an FFG developer said, "move then attack".