By Sandra Gonzalez
October 17, 2013 at 02:00 PM EDT

David Hornsby’s reaction to being asked to preside over the marriage of his wife, Emily Deschanel, to another man is probably not what you’d expect it to be.

One reason is probably because the marriage is going to take place in the world of fiction. Another? He seems to be as big of a fan of Booth (David Boreanaz) and Brennan (Deschanel) as the rest of us!

In an exclusive behind the scenes video interview, Hornsby (It’s Always Sunny in Philadelphia) talks about how he jumped at the chance to take part in the long-awaited Bones and Booth wedding, airing Oct. 21 on Fox, after creator Hart Hanson offered him the role of priest, saying at the time, “Well, I have to do that!”

“I’m a proud husband marrying off his wife,” he jokes.

Check out the behind the scenes sneak peek at the nuptials below.

BONUS! Check out a clip from the episode below!

Bones airs Mondays at 8 p.m. ET on Fox.