Osbourne 'coined 50 Cent nickname'
Osbourne first used the name at the Black Entertainment Television Awards in 2004.
The 'In Da Club' singer - real name Curtis Jackson - said: "My name was 50 Cent until [she] said 'Fiddy' at the BET Awards and then it changed."
He added: "After that it was either/or depending on how people feel."
Fiddy is currently at number one in the European album chart, beating rap rival Kanye West to the top spot.