The current favourite dedicates a song to her following their break up, which Matt first mentioned during his audition.
In tonight's show, Matt tells cameras: "It feels incredible to be here. One minute you're looking out your window at Bromley High Street and the next you're here in the South Of France. I couldn't feel any luckier."
Recalling his sing off at the Six Chair Challenge for a place in judges' houses, Matt recalls: "The Six Chair Challenge was definitely the hardest stage for me. I remember my heart was beginning to sink when I was asked to battle.
"It was a tough experience but I learned a lot. I really want to make my family proud, especially my nan. I know she's right behind me for judges' houses and I really want to give my best performance today.
"I've got one song and I really need to bring it."
Matt says he's performing a song that's "close to my heart". He tells mentor Nicole Scherzinger and her guest judge Calvin Harris that he'll be singing She's Out Of My Life.
"That chick is hurting!" quips Nicole.
Calvin remarks: "[She dumped you] And now you're on the TV. She's sad right now dude"
After the performance, Calvin tells Nicole: "He's got a great voice. You looked like you were having a moment there."
Nicole replies: "He's got a sick voice, you haven't even heard his full range."
The X Factor 2016 airs tonight at 7:30PM on ITV.