"We have never performed together before but I am having a heart attack; I cannot wait. It's such an honour." Ariana Grande was nervous before performing her duet with Christina Aguilera on the season finale of U.S. talent show The Voice on Tuesday night (24May16). Grande was drafted in at the last minute after Christina's pre-recorded duet with a Whitney Houston hologram was axed by members of the late diva's family, who declared the quality wasn't good enough.