The cast of John Krasinski's new comedy reveal what it's like to sell a movie at Sundance

While waiting for their movie, "The Hollars," to show at this year's Sundance Film Festival, the cast is doing what actors generally do at Sundance: promoting the movie, which happens to be John Krasinski's directorial debut, and chatting in long rounds with press.

The comedy follows John (Krasinski) returning home to his dysfunctional family after his mother goes to the hospital. It also stars Sharlto Copley ("Chappie," "District 9"), the musician Josh Groban, and Charlie Day ("It's Always Sunny in Philadelphia").

Business Insider met up with the three at the festival's Acura lounge to talk about their Sundance experiences so far, why they did the movie, and what it's like to mix indies with big studio projects.

BI: Sharlto, is this your first Sundance?

Copley: Yes. With a movie. I've been here once before.

BI: And Charlie and Josh, have you been here before?

Groban: I've been here for music.

Day: I've only been to Slamdance.

BI: So for people who have never been to Sundance, how would you explain it?

Copley: It's like an over-packed ski lodge.

Day: It's hard to wrap your head around it.

Groban: It feels like summer camp, to me.

Day: Winter camp.

Groban: Yeah, winter camp. Everyone is coming from different worlds, we shot this movie two years ago, and now we've come back together and I didn't have any scenes with Charlie so we've gotten to know each other from coming here. We are all just kind of here mingling and are like, "What are you here for?" It's different from a music festival.

Copley: I feel like because it's in this lodge environment, my brain is telling me I should be on holiday, which creates a different feel with everyone. I feel like I'm on holiday with you guys. It's like, if we have time, we'd ski.

BI: But instead you're in a sponsored lounge talking to me.

Groban: Yeah, only our agents have time to ski.

Day: There is a palpable level of enthusiasm, which is nice to be around. For a lot of people here, they are having their big moments with their films.

BI: So did you guys all know John Karasinski before the movie?

Copley: Charlie and I had met him once before.

Day: Only once.

Groban: We worked together on "The Office" - we had a scene together the first time I was on and the second time he directed the episode.

BI: Was it the material that grabbed you guys to come on, then?

Day: Yeah, and his enthusiasm for it. He really was able to spin it. He had this vision for a movie and he was passionate about it and passion is very infections. You want to follow a leader and you hope that you are following them into something good.

Copley: For me it was the character. It was a chance to just do something that was a little different for me, and a genre that was different. That was the most important thing for me. I felt I could do something different.

BI: Josh, even though you've done some acting, do you still get nerves doing a movie?

Groban: Sure. You're entering an environment where you're a small cog in a very big wheel and you want to make sure whatever your involvement is you're keeping that vision rolling smoothly. And being the only non-film person on this movie, yeah, I walk into it wanting to trust my director and trust the words on the paper and do the best job I can. So there are more nerves standing on a set in a little town in Mississippi than standing in Madison Square Garden, for sure.

BI: And Josh, you and Sharlto have a lot of scenes together in the movie. Was that comforting?

Groban: Sharlto and I were in my hotel room running lines, working on beats, it was so great. One of the attractive things of doing this was not just the material and working with John, but the educational experience, and working with someone like Sharlto is fantastic. It would have been great to work with Charlie, too, but we didn't have any scenes.

Day: No such luck, pal.

BI: Charlie, was John open to your riffing, or did you stick to the script?

Day: I think we stayed pretty close to the script. We might have done moments here or there of improv.

Copley: I very often will go off script but there was very little of that for this.

BI: In choosing your movie roles, Charlie, does it come down to what fits between doing seasons of "It's Always Sunny in Philadelphia"?

Day: Absolutely. With John's movie, there was something going on.

Copley: He was nagging you.

Day: Yeah, he was nagging me. I think we had two pilots we were producing.

Copley: Did you only do this movie on your break [from "It's Only Sunny in Philadelphia"]?

Day: I think I also did press for "Horrible Bosses 2" and I was flying all over the place. I just look for stuff that's exciting or a refreshing change or a great career opportunity.

BI: How did you fit this in, Josh?

Groban: I had a week off from my tour. I think I was there for four days.

Day: There is actually a shot or two of the back of my head in the movie, which is one of the producers, it's not me. [Laughs] I wasn't available. And I can't help but think he overdid it. [Laughs]

Copley: It's going to bug you the rest of your life when you watch the movie.

BI: Studios don't make these kinds of comedies anymore. They are done at the independent level. So how do you switch up getting a nice payday with a studio movie and doing something like this that you're doing for personal reward, and I would imagine not a lot of money?

Day: For me, I'm a fan of both types of movies. I love a great independent film, but I would never want to solely be an independent film actor. I love a great big studio comedy or an action movie. To me it's always what the job is and if it's an exciting job, there's room for both.

Copley: Yeah, I think you get to a point where you'll be in a box with these big movies to some degree. I've luckily been put into a wide range of characters I've wanted to do. But to be honest, if you do one of these smaller films right, you can also make real money off of them. The "Hardcore Henry" movie that I did, which was done on a shoestring, for example. I go for films that I believe people are going to watch. I don't want to be in a film that I don't think anyone is going to go see, so for me a small film like this that touches people, it can become a big film, in terms of people watching it. To me, I want to share what I do with the most number of people.

"The Hollars" screens at the Sundance Film Festival on Friday.