The Tony-winning Book of Mormon triumvirate reunited in Los Angeles last week for a week-long work session for tonight's episode, titled "Broadway Bro Down." While Lopez, Stone and Parker had seven years to develop The Book of Mormon for Broadway, things work a bit faster at South Park Studios.

"It's a hugely fast turn around," Lopez told Playbill.com. "I don't think any other animated show works this way. We started with no idea on Thursday, and by the following Wednesday, the show is broadcast. So, the writing, the character voicing, the animation, the music all happened in the space of a week."

Lopez, also a Tony winner for Avenue Q, flew to Los Angeles last week to begin work on the episode with his Emmy-winning pals. "We sat around last Thursday for about five hours before this idea emerged. It was a little bit nerve-wracking to be honest. We kept coming up with ideas, then ten minutes later we had another idea, and so on. So it felt like we were never going to settle on a story. But by the end of the day, we knew we had something cool and funny to write about."

In "Broadway Bro Down," Stan's parents Sharon and Randy make an effort to spend quality time together by seeing a hit musical in Denver. Randy gets hooked on Broadway and the two are whisked away to New York City where they catch every musical on Broadway.

Lopez said he wouldn't describe "Broadway Bro Down" as a full-on musical episode, but there are songs and what he characterizes as a "bizarre" montage of musicals; Wicked is among them. Audiences won't see send-ups of The Book of Mormon or Avenue Q, but Lopez teases that there is a joke involving one of the shows. The episode also features the voices of Kate Pazakis (South Pacific, Jerry Springer the Opera) and David Burnham (Wicked, The Light in the Piazza).

In addition to his work on "South Park," Lopez revealed to Playbill.com that he also penned an original song for "The Simpsons" a few weeks ago. The episode isn't expected to air for several months.

Getting to work on "South Park" was a lifelong dream for Lopez, who laughed, "It honestly didn't feel any different than working on The Book of Mormon, but I would pinch myself and think, 'Hey, you're working on 'South Park,' one of your favorite shows ever!'"

Lopez also hinted that when he reunites with Stone and Parker for the 2012 national tour and Chicago productions of The Book of Mormon, the trio might have time to sit down and brainstorm another musical project.

"South Park" airs at 10 PM ET on Comedy Central. Check local listings.

For now, here's a sneak peek: