Mark Ronson's Uptown Funk has reached the one million sales mark, 10 weeks after it was first released, according to Official Charts Company data.
The hit single, by Ronson and Bruno Mars, becomes the 158th track to reach the million mark in British charts history.
Ronson said it was "an amazing milestone to be in this club with all these massive superstars".
Earlier this month the single became the most-streamed track ever in the UK.
Uptown Funk - which was rush-released after it was performed by X Factor runner up Fleur East in December - achieved 2.56m streams in a single week.
However, its reign at the top of the charts appears to be over after Ellie Goulding's Love Me Like You Do held on to the top spot for a second week.
The song, from the soundtrack to the Fifty Shades Of Grey film, became the UK's most listened to track on streaming services this week, notching up 2.25 million audio streams.
Also the fastest-selling single of the year so far, Love Me Like You Do is Goulding's second number one.
Hozier's Take Me To Church climbed back to number two - after 21 weeks on the chart - with Uptown Funk rounding out the top three.
DJ Fresh's Gravity, featuring Ella Eyre, entered the charts at number four, and Rihanna, Kanye West and Paul McCartney's FourFiveSeconds completes the top five.
In the album charts, Sam Smith's In The Lonely Hour regained pole position following his success at the Grammys last weekend - marking his 38th week in the top 10.
Drake's If You're Reading This You're Too Late stole into third place following its surprise release on Friday, behind Ed Sheeran's X at number two.
This week's top 20 albums offered some old faces and some new faces: acoustic singer-songwriter Jack Savoretti made his top 40 debut with Written In Scars at number 13; Grammy award-winning jazz singer Gregory Porter reached a personal high at number 10; and Alanis Morrisette's Jagged Little Pill re-entered the charts at number 16, 20 years after it was first released.