The hip-hop star, real name Robert Phillips, passed away on Friday (09Oct15) following a stroke last weekend (03-04Oct15), according to TMZ.com.

Phillips joined the rap group in 1991, but left in 2000 after he was incarcerated. He reunited with his pals in 2012 and was reportedly working on a solo album at the time of his death.

His bandmate DJ Paul has paid tribute to the rapper in a statement which reads, "Everyone who knew Koop knew he was very funny and the coolest guy ever! He will be missed!!!"

Former Three 6 Mafia member Juicy J has also shared his condolences in a post on Instagram, writing, "R.I.P koopsta Knicca we made history! You will be missed #mafia4life prayers up for the family (sic)."

The sad news comes two years after group member Lord Infamous died of an heart attack in 2013.