Every question and answer panel at a convention is different. Sometimes the atmosphere is intimate and feels like you're talking to someone you admire one-on-one, even if you're not the one leading the interview. Other times it can still be a regular question-and-answer panel, but the celebrity beams so much positive energy, it feels more like a party than anything else. Maybe you even feel like you're at a comedy club as the celeb takes centerstage to talk to the fans, tell adventurous stories, and even sings. Both of the latter is what you'll find with David Tennant and John Barrowman. So much so they should be must-attend events at your next convention.