Music mogul Jermaine Dupri is convinced he could have helped tragic Kris Kross star Chris 'mac Daddy' Kelly if he had known about his drug use.

The rap star died of a suspected drug overdose on Wednesday (01May13) after reportedly using both cocaine and heroin the night before his passing.

His former mentor Dupri, who discovered Kelly and his Kris Kross bandmate Chris 'Daddy MAC' Smith in 1990, admits he had no idea how serious his substance abuse trouble was, and wishes he could have intervened to save him.

Dupri tells Us Weekly, "If I would have known, I would have tried to put my foot forward to help the situation. I'm hearing about this (alleged overdose) just like everybody else and I'm not really too believing of all of it (sic), but at the same time, I can't say that I didn't know. I wasn't there to know about it and I hate it because I feel like if there were people around and knew about it, then they should have waved the flag."

An autopsy has been completed, but officials are waiting on toxicology results before releasing the cause of death.

Meanwhile, TLC stars Rozonda 'Chilli' Thomas and Tionne 'T-Boz' Watkins have added heartfelt tributes to their pal.

Watkins says, "It breaks my heart to see another young talent gone too soon. I will never forget the chance I was given by Jermaine Dupri and Kris Kross to sing on their demos. They played a big part in me finding my signature sound. I will forever be grateful. I send my love and blessings to Chris' family."

Thomas adds, "I used to hang out at his house with his mum and pick him up. He was like a teenager and just the sweetest thing, just a regular cool teenage boy, so we were really close... He was really sweet, very down to earth... They were huge (but) he had a really humble spirit."