Hank Azaria and Shawn Levy, the co-star and director of the fantasy comedy Night at the Museum 2: Battle of the Smithsonian, told reporters that they were surprised they were allowed to do a comedy bit featuring the actors facing off against both Star Wars' Darth Vader and Sesame Street's Oscar the Grouch.

"That was something that Tom [Lennon] and Ben [Garand] wrote in the very first draft of the script," Levy said in a news conference at the Smithsonian last weekend in Washington. "Honestly, I read it, and I was like, 'This is awesome, but there is no possible way you are going to get Oscar the Grouch and Darth Vader in our movie.' I thought it was a complete fantasy. I still can't believe it."

In Night at the Museum 2, Azaria plays the main villain, Kahmunrah, an Egyptian pharaoh figure stored in the Smithsonian archive. Dexter, the capuchin monkey from the New York Museum of Natural History, brings the magical Egyptian tablet to the Smithsonian in Washington, and it brings life to, among others, the film's Axis of Evil: Kahmunrah, Ivan the Terrible (Christopher Guest) and Al Capone (Jon Bernthal). Azaria also voices two other characters in the film: Rodin's Thinker and the Lincoln Memorial statue of the president.

Azaria and Levy spoke alongside screenwriters Ben Garant and Tom Lennon and cast members Robin Williams, Ricky Gervais, Ben Stiller and Amy Adams at a press conference; the following is an edited version of that news conference. Night at the Museum 2: Battle of the Smithsonian opens on Friday. (Spoilers ahead!)

How did you come to voice two other characters in the film?

Azaria: That was done on the fly. We really just tempted those in while we were shooting. We didn't know they were going to end up in the film. Lincoln was hard, because you don't want to diminish him, and yet you want to try to be funny. I did a lot of versions of that, and they had to cut me off. I wanted to keep going. I wanted another four cracks at it; I couldn't stop.

Levy: Hank did those voices as a favor for me so that I could edit the scenes. The intention was always to then go hire other voices. In fact, I did go and hire other voices, but no other actor was working quite as great as Hank's takes.

Azaria: [deadpans] Yeah, but this was my question.

Gervais: Wow. After all those nice things, you still go after him? [audience in hysterics] Hold on, can I just say I think that Hank Azaria is one of the greatest actors in the world? [looks at Azaria] Go on. [laughs]

Stiller: With Darth Vader, didn't George Lucas have to say it was OK?

Levy: Oh, yeah. We literally had to go to the top of the food chain with both at Sesame Street and George Lucas, and they said yes. It was always this hilarious scene where Darth Vader was going to try the choking gesture [on Kahmunrah] from Star Wars, but then Hank riffed all the stuff about Vader being an asthmatic and wearing a cape. Are we going to the opera?

Stiller: Did George Lucas have to approve the final version?

Gervais: There's a lawsuit coming. [laughs] [Edit: We think this is a joke.]

Azaria: Yeah, but all the Jar Jar [Binks] stuff was taken out. [This is also a joke.]