Girls Aloud, who were formed on a reality TV show, sold 37,000 copies of their first album in its first week. And Pop Idol winner Will Young sold 187,000 copies of his debut album, but even that's been eclipsed by Leona's massive record sales.
Leona was also picked to sing at the closing ceremony at the Olympics in Beijing in August - which is a big honour for such a young, new star.
Success in America
One of her biggest achievements so far is to make it big in America. In March, Bleeding Love got to number one in the US singles charts - she's the first British woman in more than 20 years to do that.
A second album is planned for late next year. So 2009 already looks set to be another year massive for Leona.
As music expert Paul Stokes, from NME magazine, said: "The rest of the world tends to copy America, so if you can make it there - to use an old cliche - you can make it anywhere!"