Although they have known each other for 20 years, they have not sung together since leaving Laine Theatre Arts in 1998.
The pair will sing iconic duets, as well as solo numbers. The concert feature a live band and will be musically directed and arranged by Craig Adams.
Ellis, who is starring as Grizabella in Cats in London, said “We are thrilled to be sharing the Prince Edward stage and have already started planning our set. We love each other’s work and can’t wait to sing together.” Louise added, “It’s going to be an amazing night and we can’t wait to entertain our fans with a truly memorable evening for all of us!”