CBS' The Big Bang Theory has been making a big bang indeed, notching some of its largest audiences ever. Has geek become chic? "I think it's really just word-of-mouth," Johnny Galecki (aka Leonard) says in this 2-on-1 video Q&A. "The show struck a chord." Adds "roommate" Jim Parsons (Sheldon), "People got to find it on their own."

Galecki goes on to discuss Leonard's new romance with guest-star Sara Rue's Stephanie. Parsons jumps in to say, "This is a very important relationship for [Sheldon]", as well! But might it elicit a jealous reaction from Leonard's almost-girlfriend, Penny (Kaley Cuoco)? "I hope a subtle one!" says Galecki.

At the 2:20 mark, Parsons offers his reaction to the show's recent declaration of Sheldon's "asexuality," then Galecki shares his take on the possible casting of Leonard's mom. The boys wrap things up with Parsons naming his favorite geek-shirt of Shel's, and then both of them naming the cast member who is most like his/her character (4:00).

Big Bang airs Mondays at 8 pm/ET.