Nathan Fillion first broke out as the captain on Joss Whedon’s short-lived but much beloved space/Western hybrid “Firefly.” Since then, both he and Whedon have gone on to mainstream successes – Fillion on TV’s “Castle,” and Whedon with “Marvel’s The Avengers” – but the old pals stayed close and have a new collaboration, the low-budget, black-and-white Shakespeare adaptation, “Much Ado About Nothing,” which expands nationwide this weekend.

And if that wasn’t enough, Fillion lends his voice to Johnny, the B.M.O.C. at Disney/Pixar’s “Monsters University,” which also is in theaters now. Fillion sat down with Yahoo! Movies to discuss fitting these diverse movies into his busy TV schedule. He also revealed how his only training in Shakespearean acting was done in Whedon’s backyard, and his devious plans to one day take over the lead in the upcoming Marvel series, “Agents of S.H.I.E.L.D.”

If I were to tell you five years ago that you would be in a Shakespeare adaptation and a Pixar movie on the same day, what would you have said?

Nathan Fillion: Who do I have to kill? I would be pretty excited about that.

Who did you kill?

NF: The last hiatus [from “Castle”], I did two days in Vancouver for “Percy Jackson: Sea of Monsters” which comes out next month. I did probably less than eight hours of work for “Monsters University” for Pixar, that’s coming out. And I did three days of work on “Much Ado,” which just premiered.

It may look to the outside world like I’ve taken over summer in some way and that I’ve been incredibly busy. But really I’ve just been fortunate enough that people have allowed me to participate in projects that don’t interfere with my “Castle” work schedule. They allow me to work on weekends. They allowed me to slip in and do something and run back out and everybody is giving me a nice piece. I’m getting nice pieces of some beautiful projects. [Read the full Interview]