Julie's plans are dashed by a burst pipe; Idina Menzel gives the Greenies a pep talk, inspiring an alternative.
Chris Colfer teaches the Greenies about the importance of words as they tackle the script for their mashup musical.
When Josh Groban visits for Julie's birthday, he teaches the Greenies to sing from the heart, in perfect harmony.
When Peri is disappointed about playing an ogre, Alec Baldwin reminds the Greenies that acting is about pretending.
Married dancers Tiler Peck and Robert Fairchild teach the Greenies some ballet basics.
Sara Bareilles teaches the Greenies to create their own melodies -- but combining lyrics and music takes teamwork.
The Greenies are not focused during their run-through; improv expert Ellie Kemper tries to help out.
Fizz turns to violinist Joshua Bell for musical guidance; the friends learn that playing musical instruments requires lots of practice.
Julie asks Bill Irwin to help calm Riley's fears and to teach everyone about the circus arts.
Missing percussion instruments force the Greenies to improvise -- with some help from the cast of "Stomp."
Tituss Burgess and an array of colorful costumes help the Greenies bring characters to life.
Director David Hyde Pierce tries to help the Greenies straighten things out after their first dress rehearsal is a mess.
The Greenies are ready to share their show with an audience, including a very important guest.