According to Groban, they both love to laugh, and they're both huge nerds.
When asked by Ellen if he was okay with Dennings outing him as a nerd, Groban laughed, saying, "That’s been out there since at least sixth grade I feel like."
But it turns out that it's all their common interests that make them such a brilliant fit.
"She's such a brilliant and funny person," Josh gushed. "Humor is such a huge thing for me so, you know, the fact that we could talk about Monty Python and all sorts of weird other things, I was like, 'Ok, yeah we're on the same page.'"
And really, can any couple ever really make their relationship work if they don't share a love for Monty Python?