Teen star Miley Cyrus will be a billionaire by the end of the year, reports say.

The 15-year-old is officially the wealthiest child in the world following her success in Disney Channel series Hannah Montana.

According to People, the franchise will be worth 500 million ponds (US$987 millon) by 2009, while Cyrus earned 9 million ponds (US$17.8 million) last year alone.

A Disney spokesperson said: "Kids are earning more and more and can command huge fees in Hollywood. But no one could have predicted how popular Miley would be. She's a true star."

Mum Tish Cyrus added: "A lot goes into her investment fund, which she can't touch until she's 18."

The singer/actress completed a 69-date tour last year, with her 3-D film Hannah Montana & Miley Cyrus: Best of Both Worlds Concert Tour taking around￡14 million in its opening weekend. She has also agreed a seven-figure deal to write her autobiography.

Other young stars on the rich list include band the Jonas Brothers and actresses Dakota Fanning, 14, and Abigail Breslin, 12.