Simon Cowell has revealed he was ‘blown away’ by Rebecca Ferguson‘s performance on The X Factor.

The former contestant sang her debut single Nothing’s Real But Love on Sunday’s results show and Simon – who quit the judging panel to focus on the US version of the talent competition – proved he’s still a fan of the ITV original.

He tweeted: “I am absolutely blown away by @RebeccaFMusic, her album, her performance. Congratulations!”

Rebecca, who wore a black and gold dress for the appearance, revealed she’d had ‘the most incredible night’, but admitted she’d been nervous before taking to the stage.

“It was quite nervewracking, but I enjoyed it,” she confessed on spin-off show The Xtra Factor.

She also defended Janet Devlin’s singing style, amid claims the young hopeful had become too predictable.

“I love her. I think she’s brilliant, she’s got a lovely tone to her voice,” she said.

“I had the same thing when I was on the show, and I think there are so many artists, for instance Adele’s one of them, and they stick to their niche and I think (Janet)’s one of them.”