Cadet has died in a car crash on the way to a gig in Staffordshire.
The rapper’s family shared the news on his official Instagram account.
“We the family of Blaine Cameron Johnson otherwise known as Cadet (Underrated Legend) would like to share the sad news that during the early hours of 9th February 2019 he passed away.”
In a statement to Radio 1 Newsbeat, his management said the 28-year-old was as passenger in a taxi.
He was on his way to Keele University where he was due to perform.
DJ Semtex posted on Twitter: “I can’t believe it”, adding that it was going to be Cadet’s year.
Cadet regularly appeared on BBC Radio 1Xtra performing at MistaJam’s Christmas Party last year.
He was due to perform at Wireless in July. The festival’s website reads: “The proclaimed “Underrated Legend”, Cadet, stepped into the music scene during the second half of 2015 with a hard-hitting freestyle reaching over half a million views in just a few months.
“This was quickly followed by another heartfelt freestyle, Cadet is tipped for an unstoppable career.”