Bret McKenzie gives 'The Muppets' new songs

“I guess Jemaine was Kermit, and I was Miss Piggy,” said the bearded and curly-haired McKenzie, grinning at claims that he is actually a Muppet. “The film had very specific song placement, so I had to write them to fit new characters and everything, but it's not that dissimilar to writing for the Conchords.”

McKenzie started by writing the grand song-and-dance opening number “Life's a Happy Song,” which is reprised in another huge musical spectacle at the end of the film.

“In order for a comedy song to work, you can't have too much production in the way because if it goes too big you lose some of the comedy. So within the Muppets film, it gets big, but then it also strips right back down,” McKenzie said, who is reuniting with Clement for a New Zealand tour in June.

In addition, McKenzie co-wrote “Me Party,” a duet for Adams and Miss Piggy, and “Let's Talk About Me,” a hip-hop baddie's theme for Cooper, which meant he got to coach the Oscar-winning actor on how to rap. He turned “The Muppet Movie's” classic anthem “The Rainbow Connection,” which earned Paul Williams and Kenny Ascher a best original song Oscar nomination back in 1980, into a heartwarming reunion number for Kermit and his pals.

“We just tried to respect the original,” McKenzie said during the filmmakers' news conference.

He also developed plenty of respect for longtime Muppeteers Steve Whitmire and Dave Goelz, who had insight into the franchise that even the superfans didn't know.

“We were recording this big number with lots of Muppets singing, and I was like, ‘OK, and the chickens ...' And they were like, ‘Ah, the chickens can't sing. They can't talk,'” McKenzie said. “‘OK, but frogs can?' ‘Every other animal can talk, but chickens can only cluck.' It's like, ‘OK, guys. All right, chickens, let's do this.'”