Nothing else is likely to beat it either, given that it shifted 295,000 copies in seven days, dwarfing the highest first-week sales of artist-led albums in 2012 by almost 200,000.
But why do the public, in an age where they can download exactly what they like, when they like - for as little as 59p in some cases - buy a full compilation record? We've looked at some reasons below:
The Now! series appeals to those who don't regularly buy music anymore.
As single sales continue to grow, so does the amount of new songs released each week. For those who struggle to follow the weekly goings-on in the charts every week, the Now! compilation serves as a handy summary of the most popular songs released over the last few months for those without the inclination to search out music via any other route.
They're generally released at 'gifting' times in the year.
Three Now!'s are released each year; in April, July and November. The November album is obviously aimed at the Christmas market, while things like Mother's Day, Easter and summer holidays make it an easy present earlier on in the year. In fact, April's Now! 81 is technically the biggest-selling album of 2012 so far (compilations are counted separately by The Official Charts Company), having shifted over 700,000 copies.
They're backed by a big, expensive ad campaign.
The advertising around each Now! compilation is near-unavoidable. Its ubiquity means the TV ad can be played round the clock across all channels, while its push online is equally as strong (it dominated the iTunes store homepage last week). It also serves as the perfect "supermarket album" - i.e the sort of record a casual shopper will pick up on impulse, probably because it's been pushed in their face via a garish point-of-sale as soon as they enter the store.
Will it be the last one?
Many people will continue to buy the Now! series purely out of tradition, meaning some of those who were bought and enjoyed them as children will continue to buy them for their children/siblings/nephews/nieces/etc. If reports are anything to go by, this year could mark an end to Now! (although it most likely won't), which may also go some way in explaining its huge sales.
Why do you think the Now That's What I Call Music! compilations are so popular? Leave your comments in the box below: