Even as he reaches the peak of fame, the teen heart-throb Justin Bieber already faces the prospect that, not too long from now, his star will be eclipsed by a younger, even more precocious talent.
Thousands of teenage fans poured on to the streets of London last week to welcome the Canadian singer, who had arrived in the UK to promote his new film, Never Say Never. He also picked up a Brit award on Tuesday for Best International Breakthrough Act. At the age of 16 he is undoubtedly social networking's first global superstar: he has 21 million friends on Facebook and is the most viewed person on YouTube. But already he faces a challenge from would-be successors.
The latest emerged last week in the form of 10-year-old Heather Russell. She sings and plays the piano with a facility way beyond her years. She even writes her own songs. Simon Cowell saw her on YouTube, and the unknown prodigy quickly joined Susan Boyle and Leona Lewis on his Syco label.
The most likely heiress apparent is Charice Pempengco, the Philippines' answer to Whitney Houston and a veteran at the age of 18. Her television debut aged seven led to TV appearances in the US by the time she was 16. She made an appearance in two of the gala events surrounding Barack Obama's inauguration and debuted on British TV screens in Glee this year.
With record companies facing a global collapse in sales, there is a desperate scramble to find the Next Big Thing, even if it is barely out of nappies.
Websites such as YouTube play a big part. Peter Robinson from the pop commentary website Popjustice said: "Record label talent scouts do look at YouTube. If you want a pop icon for your roster, trawling the clubs of Camden isn't the way to do it any more. Five or six years ago there was no direct link between an artist and the fans. There is now a completely direct route."
Jaden Smith, 12 and Willow Smith, 10
With a combined age of 22, actor Will Smith's offspring are the epitome of precociousness. Between them they boast the titles singer, songwriter, rapper, actor and dancer. Jaden first appeared alongside his father in the 2006 film The Pursuit of Happyness and rapped alongside Justin Bieber in the song "Never Say Never". His younger sister Willow, meanwhile, launched her music career last year, signing to Jay-Z's label. She released a single, "Whip My Hair", which reached No 11 in the US.
Heather Russell, 10
Canadian Russell was signed by Simon Cowell after he spotted the youngster on YouTube. She cites Prince and Queen among her influences. Russell started her career auditioning for talent singing shows, aged eight. Posting a clip of herself performing her song "Every Step of the Way" on the internet video site, she initially attracted more than 100,000 viewers, including celebrity fans Demi Moore and Ashton Kutcher, who helped to spread her name by tweeting about her.
Jackie Evancho, 10
A mezzo-soprano, Evancho sings in the classical crossover style of Sarah Brightman or Susan Boyle, though she is young enough to be their granddaughter. She was inspired to sing by watching a DVD of The Phantom of the Opera at the age of seven. Participating in talent contests she started her own YouTube channel, which caught the public's notice: appearances on Jay Leno's and Oprah Winfrey's TV shows followed.
Charice Pempengco, 18
The Filipina singer hailed by Oprah as "the most talented girl in the world" is the first Asian solo artist in history to land in the top 10 of Billboard's album chart. Raised by a single mother, she helped to support her family by entering singing contests from the age of seven. But it was a performance aged 15 on a Korean TV talent show – later seen by millions on YouTube – that brought her international notice. Not content with comparisons to Mariah Carey and Whitney Houston, Pempengco has moved into acting with appearances in Glee.
Bianca Ryan, 16
After winning the debut season of America's Got Talent five years ago, the 16-year-old singer and guitarist recently toured the world. Her father, a Rolling Stones fan, named his second child after Mick Jagger's ex-wife. In 2006 she signed a five-album deal with Syco Records, becoming the first US artist to sign with Simon Cowell's record label.
Born Jamia Simone Nash, she made her national televised debut at the age of five, performing on the US music show Showtime at the Apollo. Born in 1996, the US child sensation began singing at the age of two and has since shared the stage with Stevie Wonder and Alicia Keys. She also counts acting among her talents and appeared in the 2007 film August Rush. In 2008 she sang the film's main song "Raise It Up" at the Oscars – the youngest performer to do so at the ceremony.
Makisig Morales, 14
At only 10 years old, Filipino Morales competed alongside his sister Mayumi in the TV singing contest Little Big Star. It was his big break and led to him signing with the country's Star Records, becoming lead singer of the boy band Mak and the Dudes. The group is the youngest in the Philippines. They released a debut album, Oldies But Kiddies, in 2007. Morales has accumulated a string of acting roles, in children's films and TV shows.
Amy Diamond, 18
As the youngest person in Sweden to release a best-of album, Diamond – born Amy Linnéa Deasismont – has already made her name in Scandinavia as a pop singer, actress and television presenter. Her first single, "What's in It for Me", released in 2005 when she was 12, became the most-played song in Poland that year. An album followed on the back of its success. Now, with six albums to her name, she is a firm fixture on Swedish television.
Keke Palmer, 17
Born Lauren Keyana Palmer, but known as Keke. Her family saw her star potential at a young age and relocated to California from Chicago so she could pursue her singing and acting ambitions. Palmer signed her first record deal with Atlantic when she was 12; the following year she was performing in packed stadiums. Her debut album So Uncool was released in 2007. Keke also launched a cut-price fashion line through Walmart.
Zara Larsson, 13
Born Daniel Sunebrink in 1997. Zara's parents noticed her singing talent at a young age and helped to get her singing career off the ground. She first appeared in a stage production of The Sound of Music before going on to compete as a finalist in the Swedish talent show Stjamskott in 2007. A year later, she won the Swedish version of Britain's Got Talent, performing versions of Whitney Houston's "One Moment in Time" and "My Heart Will Go On" by Celine Dion.