Anna and Elsa return to the big screen March 13 when the short Frozen Fever accompanies Cinderella in theaters. Jennifer Lee and Chris Buck return to the directors’ chairs in this follow-up from Walt Disney Animation Studios.

The short will feature a new original song by Frozen Oscar winners Robert Lopez and Kristen Anderson-Lopez and will involve a summer solstice birthday party for Anna gone awry. The original voice cast will return: Kristen Bell as Anna, Idina Menzel as Elsa, Josh Gad as Olaf, and Jonathan Groff as Kristoff.

Just released from USA Today, here are five stills from Frozen Fever:

Even though it’s a short, the Disney team did a great job making the designs unique, specifically the girls’ wardrobes. Both Anna and Elsa get new spring-inspired outfits for the short, although the basic designs and shapes are very similar to their original dresses we saw in Frozen (pictured in the final picture above). Anna is decked out in a beautiful green and teal dress, with decorative rosemaling. Elsa’s iconic blue dress is now a lovely shade of green, featuring pink and purple accents and flowers.

Co-director Chris Buck points out some further background: The short will reverse-parallel Frozen‘s opening moments as Elsa wakes up Anna. Additionally, the birthday premise comes from Elsa’s yearn to make Anna’s day special, the sisters having never celebrated birthdays together growing up.

[UPDATE] 10:40 AM PST: Disney also released a featurette about Frozen Fever. Check it out!

Frozen Fever arrives March 13. Are you ready?