Rak-Su have been crowned winners of the X Factor 2017 in the first ever final where only original songs and not covers were performed.
The four-piece beat Grace Davies, 20, into second, becoming the first group to win since Little Mix in 2011 and the first boy band to win it. They did better than global megastars One Direction, who only managed third place in 2010 but went on to sell 70 million records.
The Watford-based group, comprised of Myles Stephenson, Jamal Shurland, Mustafa Rahimtulla and Ashley Fongho, all 25 and 26 , were stunned when their group's name was read out by presenter Dermot O'Leary.
Jamaal said: "I just want to thank everyone at home, everyone here, all my friends and family who made this special, I'm speechless."
They are only the second band to win the show overall in the series' 14 seasons and with their win, they will release their own original song, Dimelo, which they performed with Wyclef Jean and Naughty Boy in what will be the first time the champion has released a winner's single as a duet.
Grace Davies performed the first song Nothing But Words. This was followed by Rak-Su with their new song Touche which got a rousing reception from the audience at London's Excel Arena.
An emotional Cowell who mentored the group called them "gentlemen", adding: "You are stars."
He compared them to 1D, saying: "There's an awful lot of artists in entertainment who appear nice in front of the cameras but behind them they're monsters.
"Not these guys. These guys have that same thing as 1D, a certain class," he added, according to the Sun.
He also praised runner-up Davies, saying: "Congratulations to Grace who is really an outstanding, outstanding artist," ITV News reported.
The final saw star performances from Pink, Sam Smith and Little Mix, who won X Factor themselves in 2011.
For the first time, all the money raised from the winning track will go to children's hospice charities Together For Short Lives and Shooting Star Chase.