The British star has had a hugely successful career both in Hollywood and in musical theatre, including Broadway’s revival of The Colour Purple, the Sister Act UK Tour and The Umbrellas of Cherbourg.
It was recently announced she will play Elphaba in the big screen adaptation of musical Wicked alongside Ariana Grande.
Speaking of her guest judging role, Cynthia said: “I’m so delighted to be joining the Strictly judging panel for Musicals Week. Musicals have a unique place in my heart, it’s such a special way of connecting all art and making it one.
“I’m excited to bring my experience to the show and I can’t wait to see what the couples have in store this weekend.”
Strictly bosses announced earlier this week that Craig would miss the show but would return the following week “all being well”.
Musicals Week will see the remaining couples perform routines to show tunes from some of the most loved musicals of all time.
Strictly Come Dancing continues on Saturday at 6:35pm on BBC One.