These 4 friends from Watford are Jamaal, Ashley, Mustafa and Myles.
According to the band, the name Rak-Su comes from 'Tracks vs Suits' meaning 'Music and fun vs Adult Life'. Makes sense.
It's a bubbling soup of different styles, including future R&B to hip hop, grime, spoken word and everything in between. Something for everyone, then!
Now they have the X Factor crown – not a real crown, obviously – the band say they "just to keep making more music and spread more vibes".
The band sang a version of Justin Timberlake's Señorita, but Simon Cowell wanted to hear their own original music. They performed I'm Feeling You and got through to the next round!
They've have had 7 songs in the iTunes Charts including: Mamacita, Mona Lisa, I’m Feeling You, Faith, Flowers and 2 versions of Dimelo, one of which also features Wyclef Jean and Naughty Boy.
Rak-Su are the first boy band to win the TV competition. The only other group to win The X Factor was Little Mix in 2011.
Simon Cowell, who also looked after The Cutkelvins, Jack and Joel and Sean and Conor Price.
The 4 performed Dimelo, Mamacita (with Naughty Boy & Wyclef Jean), Touché and Mona Lisa.
The day after winning the competition, the band posted a message on Twitter which said: "Last night was a dream! You guys made us feel like rock stars yesterday the energy was unreal and the response was incredible! Thank you for making last night 1 of the best nights of our lives!"