The last time he emerged from an X Factor final as a winning mentor, Leona Lewis was the act who came out on top.

So it’s no surprise Simon Cowell was an especially happy man tonight as he had his two favourite girls in one place.

Before Melanie Amaro was announced as the X Factor USA winner this evening the music mogul beamed about how happy he was to have the 26-year-old back on the talent show stage.

When the show’s host Steve Jones handed the floor over to him following her heartfelt performance, the 52-year-old, reminisced about the days when he discovered her, five years ago on the British version of the show.

‘I can remember being in his position with her at the very same stage of this competition.’ He said. ‘Thank God she won. She is a brilliant artist.’

Nicole Scherzinger – who was mentor to Josh Krajcik - was also very complimentary of her.

After Lewis showed the X Factor finalists how it was done, the fellow singer said: ‘Leona blessed us with her beautiful voice.’

Simon’s protégé, who has gone on to have massive success after winning the X Factor UK in 2006, looked stunning in a cowl neck gown and lashings of red lipstick, she sang her famous rendition of Run by Snow Patrol.

Playing in the background was a montage of moments from the current show bringing some of the judges to tears.

The humble star also performed on the UK final of the show where she sang a cover of Nine In Nails' Hurt.

Credible English rockers, Coldplay, made their debut X Factor performance that night as they played their track Paradise to a 10,000-strong audience.

While Cowell’s friend, Paula Abdul, who followed him out of his panellist post on American Idol, described the first American series of the show as ‘one of the most exciting job experiences I’ve had’, L.A Reid - who mentored finalist Chris Rene - described his time as ‘an emotional journey’ and told the Welshman that his favourite moment was ‘watching Dexter jump into the pool.’