VIDEO : Exclusive! Derek and Julianne Hough Are Performing Together During the DWTS Finale

E! News has exclusively learned Derek and Julianne Hough are set to perform together during Dancing With the Stars' season 20 finale on Tuesday.
And it gets even better.
The fan favorite pro and judge will be dancing during a special performance by Sia, who will be performing "Elastic Heart."
Who's choreographing the siblings' routine? Derek will, who interestingly performed Sia's "Chandelier" when he faced his sister on Spike's Lip Sync Battle!
This will be the second week in a row fans have been treated to a performance by Julianne, a former pro herself.??