Rak Su finished the night's performances, teaming up with Grammy-award winning rapper Wyclef Jean on Rak-Su's original song Dimelo.
And, after watching Ashley, Jamaal, Myles and Mustafa belt out their final song, Simon told them: "Not many artists with this much at stake rather than just doing something before, or doing an old song, you stuck to yourselves". On Saturday, One Direction's Louis Tomlinson performed new single Miss You, while LA boyband PrettyMuch performed their debut single No More live for the very first time.
He also praised runner-up Grace, saying: "Congratulations to Grace who is really an outstanding, outstanding artist".
They then performed their winners' single again, with Grace and the rest of The X Factor 2017 contestants joining the band on stage.
The I'm Feeling You singers looked stunned as host Dermot O'Leary announced they had won the show, before hugging each other and their mentor Simon Cowell.
The foursome triumphed over Grace Davies during the live final from ExCeL London on Sunday night, in a show that performances of their original songs Mona Lisa and Touche.
Simco Limited will donate 100% of its profits from the sale of each download and in respect of all audio streaming of the single, and the Chancellor has also agreed to donate the Value-Added Tax, in each case to be shared equally by Together For Short Lives and Shooting Star Chase.
"This is what we're gonna try and do this weekend, we're gonna try and raise a million pounds for this charity". You can go to the website, donate whatever you can. "All the proceeds from the record [the winner's single] will go the charity".