Natalie Okri from south London has been singing since the age of four and told the judges: "I sing at home and I sometimes even sing when I am having my dinner. I want to be a singer and a diva and I definitely want to be like Beyonce."
The youngster sang No One by Alicia Keys - and Piers Morgan responded: "You are a very very little girl with a very very big voice, I loved it."
Cowell added that she was "totally and utterly adorable".
Judges also see 11-year-old Aidan Davis from Birmingham who was so impressed watching George Sampson on the show last year that he was inspired to give the auditions a go himself.
Dancing to Low by Flo Rida and featuring T-Pain, Aidan showed off his home-taught dance moves.
Morgan said: "When George won last year we all feared we'd get millions of little Georges trying their luck that wouldn't be anywhere near as good as him, but I think you are as good as George."
Cowell declared: "You are super, super, super talented."
The programme airs on Saturday at 8.20pm on ITV1, followed by Britain's Got More Talent on ITV2 at 9.20pm.