Willis, who will remain with the Broadway production for six weeks through Nov. 1, performed "Me and My Baby." Watch the performance below:
Willis is the winner of the TV show "Dancing With the Stars" and the eldest daughter of Demi Moore and Bruce Willis.
Chicago currently stars Amra-Faye Wright as Velma Kelly, Ryan Silverman as Billy Flynn, Raymond Bokhour as Amos Hart, NaTasha Yvette Williams as Matron “Mama” Morton and R. Lowe as Mary Sunshine.