Stone took housemates through some vocal exercises in the dance studio, before playing them the Journey original, as Ben, John James and Steve hadn't heard the song before.
Talking about the song, Stone said: "It's not as easy song to sing, it has a lot of theatre in it." He asked housemates to try and not "distract" him too much, as he wants them to "kill it" and win the task.
Housemates then sung the song together several times, so that they could "get the melody in your brain". Stone joked: "A tiny bit of Auto-Tune in there and it's all alright!"
Stone then chose different partners to sing the first two verses. Steve and Corin were up first, followed by David and Rachel. It was then John James and Josie's turn to duet, leading housemates to cheer and whistle. Stone had to teach John James the words, and told Josie she had "a great voice, but I was scared of you", pointing at her frown while singing.
Stone told Josie and John James they "looked right" for the duet, but he might not choose them as the pair. Josie said: "That was so embarrassing."
Andrew and Corin performed a passionately charged version of the song, promoting Stone to ask: "Is there something going on with you two?" He said of Andrew: "What I liked about you, is that you weren't note perfect, but you weren't afraid to go with it. We need visual as well as the vocal, no-one can fake a performance."
Finally, Ben had his turn with Josie. Stone told Josie: "The minute you smile, you light up a room."
Stone told housemates he will now pick roles for each of the housemates, which includes lead male and females and a guitar solo. He said: "You're all going to have your moment in the video."
Afterwards, David and the rest of the house teased John James and Josie, saying it was clear that they will be chosen to do the duet. He said: "They're perfect but he can't sing!" before joking that they will claim the Christmas number one.