If you have management, it's often best to approach them with this type of character. Especially if it's an issue across the office, and not just a one on one relationship problem.
Confrontation doesn't help anyone in most cases. And at the end of the day it isn't your job to mediate employees (that's what managers and HR do). They're trained to handle the situation gracefully, so you don't accidentally escalate it and damage the relationship further.