How do you think your previous employers would describe you?

Don't ask the interviewer if they talked to your previous employers. Likely, they haven't. In most states, previous employers will disclose very little about your history out of the concern of defamation lawsuits resulting from heresy. So, there's no need to feel nervous. The actual purpose of this question is to test your stress responses in real-time. So stay on course and answer with confidence. Keep your answer consistent with the rest of the interview. That will offer the interviewer greater confidence in what you have to offer.