Cowell - who guided Niall and his One Direction bandmates to fame after discovering them on the UK "X Factor" - showered praise on the 22-year-old singer and hinted that a big announcement is coming, reported People magazine.
"I think they're all gonna do great. Niall is the most loyal. We are expecting to announce something soon with him. I've always known he's loyal," Cowell said.
Singer John Newman also revealed that he has been working on new material with Niall.