Give ’em the old razzle-dazzle! On The CW’s critically beloved comedy Crazy Ex-Girlfriend, unhinged legal eagle ­Rebecca Bunch (Rachel Bloom) navigates life and love one hilarious musical number at a time. (Some previous hits, like “Let’s Generalize About Men” and “The Sexy Getting Ready Song,” have gone viral on YouTube.) The series has taken a dark turn during Season 3—delving deeper into Rebecca’s mental health issues—which is why when it returns on January 5, those lavish routines will be more essential than ever, as they offer a dose of much-needed levity. ­Making sure the show hits the mark is Emmy-winning choreographer Kat Burns, whose past credits include orchestrating some of the hijinks on The Late Late Show With James Corden as well as on Key & Peele. Here, she takes us through the steps.

When do you put together the ­routines?

Usually at the last minute! I’m in all the concept and production meetings, but until Rachel decides how she wants the numbers shot, my work doesn’t really start. Once I know the style, I usually have under a week for rehearsals.

How has the recent shift into ­seriousness impacted your work?

By the middle of the season, we stopped ­having as many big, happy dances—it wasn’t right tonally. The trickiest thing for me is ­knowing when to bring the energy up, and when to be chill. But we always find it.

What would you consider the toughest challenges?

Every actor is different, so it’s important to adapt the choreography to them and their process. Rachel has great muscle memory because she’s in basically every song. After 10 or 15 minutes, she’ll be like, “Got it!” And I always have to be ­thinking about camera angles, props, ­costumes, all of that. The biggest thing is the race against the clock, since we shoot a music video in basically half a day. On ­Dancing With the Stars, they spend at least eight hours a day for a whole week on one number—we have three hours, tops!

Anything in particular on your wish list?

My ultimate dream is to do a beautiful aerial number with, like, 70 dancers. Or something in an above-ground pool.

Or a major Rockettes kickline! It’s endless, and we still have a lot of room left to play.