Pharrell Williams' global smash hit Happy has been declared one of the biggest-selling U.K. singles of the last 20 years.

The song has reached triple platinum sales figures (1.8 million copies), and joins only three other songs - Barbie Girl by Aqua, Sir Elton John's Candle in the Wind tribute to Diana, Princess of Wales, and Will Young's Anything Is Possible/Evergreen - to reach triple platinum status since 1994.

The Happy news was announced after officials at the British Phonographic Industry incorporated online streaming into sales figures this month (Jul14), with 100 plays registering as one sale.