Transcript for Which 'Monuments Men' Star Didn't Have Fun on Set?
The monumental men gathered with me all starring in t"the monuments men" telling the story of unknown civilian men and women recruited toward the end of the war to protect works of arts stolen by the nazis. Here's a look. This photograph has been obtained by the oss. It's a model of his planned furor museum to be built in his hometown of L. Nsk in Austria. A museum. One of the biggest in the world. Take a lot of art to fill that up. That's exactly right. We already know that he's stealing art from Amsterdam, from Warsaw and from Paris, the French are hiding it. The Germans are finding it and taking it. This is why hitler didn't bomb Paris. Well, he bombed London. Yes, I know. And so excited right now to welcome George Clooney, Matt Damon, Hugh Bonneville, Jean dujardin, John Goodman and bob Balaban, good morning, America. Did you have a terrific time making this. We did. We did. George didn't. George had to work. He had work to do. It was fun. I understand when the weather got bad the teamwork really kicked in. These guys would pick up camera boxes and help us out. Everybody helped out whenever the weather got bad. It was fun. I didn't know it was unusual. I thought it was part of my contract. If you ask him this morning he'll carry something. He'll carry anything. I got the trash out this morning for you guys. Thank you. Thank you. Let me ask you how did you hear about the project and get together with George? Okay, in English, I'll speak -- Do you have one week in -- When George called me I Sa said -- Oui. No, I'm on vacation. Get out of here. No. I saw his movie before and I knew it would be interesting and fun. I don't think you could quite understand what he said. He said I'm much better looking up close is what he was saying. Bill, I understand that George gave you a little bit of a hard time in the luring you to the role. I did hear the story about a year before. The story of the film and it was such a great story, I thought, god, I would love to be in a film like that. Then it went away and I cried myself to sleep and then nine months later he said, oh, would you be interested in doing this job. I said, well, I thought you'd never ask. When you're George Clooney. When you're George Clooney you like to speak about yourself in the third person so George Clooney, you know, here's what actually happened -- He got on a plane and went to Australia personally to hand deliver the script to cate. That's true. I got an e-mail. One line. What are you doing in the spring? Literally what -- It's true actually. I just wrote back, nothing. Glad you brought up cate. Only woman in sort of the core group. What was it like working with her? She's kind of a hack, isn't she? I mean -- barely -- I feel like she learned a lot working with us, you know. Which is good. I mean I feel like she's really coming on. Put a team together. The concept is so unbelievable that this, you know, sort of motley true of civilians gets thrown in there to protect these incredible works of art. Were you surprised that we hadn't heard this story before? I had no idea that there was a group of designated people over there and I had no idea that hitler was systemically raiding all of the museums in Europe basically for his museum and at the end of this story he was going to destroy everything. Hugh, I want to ask you, your cast was just on on "Downton abbey." They have yet to reveal their passion for it. I'm sure it's hidden but I hope at least George might have seen five minutes of it or he wouldn't have cast me. I have it on a reel at my home, a loop. George, is it hard to direct a big group like this? No, I mean in all honesty this is the easiest part of it. They're all pros. It was really fun to work with them. Most -- one person I won't name one I didn't get along with. We know you're talking about me. I'm just going to really quickly wrap it up. A lot of your scenes are shot in groups. John and John did "The artist" together so there was a little -- And John and George did "Rose Anne" together. John -- let's say the show, first of all. Let's not just say we did "Ro "Roseanne" together. Thank you, I'll be here all week. I just want to say thank you for bringing this story of "The monuments men" to the attention of the country. It's an important story and great fun to watch and thank you so much for being with us on "Good morning America." Well, thank you. Thank you, Lara. That was very nice.
This transcript has been automatically generated and may not be 100% accurate.