Stevie told US gossip website Just Jared: ''I want to apologise for my remarks about Nicki Minaj's behaviour toward Mariah Carey which I said during a long and exhausting day of interviews.
''It was very out of character for me and I deeply regret what I said.
''I feel very protective toward Mariah Carey who has gone through many difficulties in her life and I spoke without thinking. I think all artists should be respectful toward one another and that includes me. I am truly sorry.''
Mariah and Nicki went head-to-head on the judging panel of the show last week, with Nicki at one point threatening to shoot the 'Hero' singer and filming having to be called off.
Stevie, who is currently promoting her new documentary 'In Your Dreams' previously told The Daily that she would have probably have been jailed for killing Nicki if she had spoken to her the way she spoke to Mariah.
The 64-year-old singer said: ''How dare this little girl!... If I had been Mariah, I would have walked over to Nicki and strangled her to death right there. I would have killed her in front of all those people and had to go to jail for it.''