Another day, another Smith family member sets out on the road to stardom

Her father has been hailed as one of the most powerful actors in the world; her mother is a Hollywood actress-turned-singer in her own right and her 12-year-old brother is a child prodigy whose debut acting role earned him an MTV movie award.

While some nine-year-old girls might sink under the weight of such extraordinary family achievement, Willow Smith, the daughter of Will Smith and Jada Pinkett Smith, appears to have raised the bar.

The youngest Smith, yet to turn 10, has secured a record deal with the rapper Jay-Z, who is also one of the most influential singer-producers in the American music industry, and who has compared her vocal skills to those of the former singing legend Michael Jackson.

Her first hip-hop-based single, "Whip My Hair", released this week, has been an internet sensation. It was viewed more than 100,000 times on YouTube on its first day of release. Jay-Z, who had the foresight to sign the R&B artist Rihanna when she was still a teenager, predicted superstardom for his latest discovery. In a radio interview, he said when he first listened to the single, he did not know the singer's identity yet felt the song was a guaranteed "smash".

"I heard the record first before I knew that it was recorded by a nine-year-old and I was like, man, that record's a smash," he said. "I believe in superstars. I believe in big records. I think she has both. She has a child's innocence but she has a clear vision of who she is and who she wants to be."

Jay-Z's record label, Roc Nation, released a statement further describing Willow's talents in glittering terms: "[She] has an energy and enthusiasm about her music that is truly infectious... Willow is about to embark on an incredible journey and we look forward to joining her as she grows in all aspects of her career."

The rapper dismissed suggestions that Willow may be too young to launch a music career. "When you have that sort of talent, there is no such thing as too young," he said.

Before her burgeoning musical career, Willow made her acting debut in her father's film I Am Legend, in 2007, and provided the voice to one of the characters in the animated movie Madagascar: Escape 2 Africa along with her mother.

The record deal is the latest success for a family who are big business in the US. Will Smith, who started out as one half of the hip-hop duo DJ Jazzy Jeff and the Fresh Prince, has gone on to become one of the most popular actors in Hollywood. With eight movies in a row grossing more than $100m (£65m), he is one of the most bankable stars in the world. In April 2007, Newsweek magazine called him "the most powerful actor on the planet".

It is clear that Mr and Mrs Smith are supportive of their children's early entry into showbusiness, and Willow follows her older brother, Jaden, into the industry. He made his debut in the 2006 film The Pursuit of Happyness, which also starred his father, at the age of eight. He was awarded the best breakthrough performance at the 2007 MTV Movie Awards in recognition of his role.

Earlier this year, he starred opposite Jackie Chan in the highly anticipated film The Karate Kid, a remake of the 1984 original.

Will Smith himself started his career as a singer. In the late 1980s, he gained popularity as a rapper, calling himself the Fresh Prince. It was only in 1990 when he launched the television series The Fresh Prince of Bel-Air that his reputation as an actor was established. By the mid-Nineties, Smith's film career was well under way with a series of big box-office blockbusters.

In 1997, Smith married Jada Pinkett. The Smiths met at an audition for his television show, in 1995. The couple appear to have one of the most solid relationships in Hollywood. She once said in an interview that she would rather "throw my career away before I let it break up our marriage".

Jaden and Willow – both of whom are home schooled – have already become red-carpet regulars. Many believe they have a confidence well beyond their years. They have an older stepbrother, Trey Smith, from Will Smith's previous relationship.

A star in her own right when the pair tied the knot, Pinkett began her career appearing in several low-budget films before landing a starring role opposite Eddie Murphy in the 1996 movie The Nutty Professor. She has appeared in numerous other films including Scream 2, two Matrix movies and Collateral, with Tom Cruise. In 2003, she helped create the metal rock band Wicked Wisdom in which she starred as lead singer.