Cadet has died in a car crash on the way to a gig at Keele University in Staffordshire.
The rapper from south London, whose real name is Blaine Cameron Johnson, died in the early hours of Saturday morning.
The news of Cadet’s death was confirmed by his family on his official Instagram account.
In a statement to Radio 1 Newsbeat, his management said the 28-year-old was a passenger in a taxi.
Cadet’s cousin Krept – of rap duo Krept and Konan – led the tributes online, saying he was “heartbroken”.
The 28-year-old had been rapping alongside Krept and Konan since he was a teenager.
His most recent single Advice, with Deno Driz, was released in October and peaked at number 27 in the charts.
Musicians, sports stars and DJs have all been paying tribute to the rapper.
Stormzy said he didn’t know what to say, posting on Instagram that it feels “mad, weird” whilst Drake simply wrote RIP.
Cadet regularly appeared on BBC Radio 1Xtra and performed at MistaJam’s Christmas Party last year.
Staffordshire Police confirmed Cadet died in the crash in Betley in the early hours of Saturday morning.
In a statement, the force said: “Blaine Cameron Johnson, 28, of London, died after the Toyota Prius he was travelling in was involved in a collision with a Vauxhall Combo van at 1.30am.
“He was pronounced dead at the scene.”
A previous statement said that the drivers of both vehicles were taken to hospital with serious injuries and three others were also being treated in hospital.
Cadet was on his way to Keele University where he was due to perform at the student union night Fresh Friday.
It’s billed as ‘Staffordshire’s Biggest Hip Hop, Garage and R&B Night’.
DJ Target posted on Twitter that Cadet was “a talent, and a lovely guy, always smiling, infectious energy.”
This year was set to be massive for Cadet
by Nick Bright, Radio 1Xtra DJ
For us at 1Xtra he was a huge artist.
Lots of his tracks were on the playlist last year, and even as we speak at the moment one of them is on the A-list, so it’s one of the tunes that gets played the most.
To see this happen to an artist just as he’s about to break through is a really sad thing.
He’s from Gypsy Hill in south London and he started out in a crew called Gipset with Krept and Konan.
He’s consistently being putting out music – the Commitment and the Commitment 2 are probably two of the most known pieces of work he’d put out.
He got so much recognition from those projects alone and lots more people have been paying attention to his music.
He’s worked with Krept and Konan, two of the biggest rappers in the UK, Donae’o and Deno Driz on Advice, which is probably one of the biggest tunes he put out there.
It’s quite a small scene so when something like this happens everybody within this industry knows it’s happened.
There’s no doubt in my mind that he would have been playing at so many different places this summer because he’s got so many big songs out at the moment and loads in the pipeline.
In 2015, Krept brought Cadet on stage with him at Wireless Festival and this summer the rapper was due to perform at the festival.
In a statement, Wireless said: “Our thoughts and prayers go out to the family, friends and fans, of Cadet.
“Such sad news.
“We’ll be keeping his Wireless performance as a time to reflect on the memory of Blaine.”