The 'X Factor' UK judge revealed the media mogul was the first to get in touch following her son Jack's multiple sclerosis diagnosis and insisted he is a better man than people give him credit for.
She told the Daily Mail newspaper: ''He's a good man. He was the first person to contact me when my son Jack was diagnosed with multiple sclerosis.
''He's a big softie underneath it all, a big old softie.''
The 60-year-old star - who is making her return to Simon's talent show after a long hiatus - also denied any rumours of a major rift between the pair.
She explained: ''We've never fallen out seriously. It was just that when Simon said he didn't like working with me I thought, 'Well, I'm going to say something mean about you'.
''Then we spoke and he said, 'Let's stop this. It's ridiculous. We're only hurting ourselves'. And I said, 'I agree'.''
He added: ''He's the biggest kid I know. He's going to spoil that child. It will be the best thing that's happened to him.''
The BBC drama starring Aidan Turner returns to BBC One on September 4th.