A young musician who signed a £1m record deal has become Britain's fastest-selling jazz star. Jamie Cullum's debut album for a major label has gone gold in a fortnight.

It is a huge achievement for a musician in the genre, who even at their peak might struggle to sell 10,000 copies. Gold discs are awarded when more than 100,000 copies are sold to shops. Cullum's album Twentysomething has sold 159,000 to record stores and its popularity with the public is soaring.

Although it entered the charts at 22 there has been huge rise in the past week and it entered the top 10 yesterday after selling about 50,000. It is expected to continue to be a big-seller in the run-up to Christmas. Cullum, 24, a largely self-taught pianist, was signed earlier this year after impressing Universal record label bosses with his performances on the bar circuit. His repertoire includes standards, his own compositions and jazz versions of songs by acts including Radiohead and Jimi Hendrix.

The upsurge in sales this week is being credited to an appearance on BBC1's Parkinson Show last weekend. Gennaro Castaldo, a chart expert for HMV, said: "If you get the right exposure to the right target audience like this it really pays dividends.''