Image copyright Getty Images

Ed Sheeran's No. 6 Collaborations Project has just become the year's fastest-selling album.

As you probably know, it's full of A-list featured-artists including Justin Bieber, Eminem, Camila Cabello, Cardi B and Bruno Mars.

What you might not know is that No. 6 Collaborations was preceded by - you guessed it - the No. 5 Collaborations Project.

Released all the way back in January 2011, it featured some of the leading names in UK rap and grime, including Wiley, Ghetts and Jme.

It was the final EP of five that Ed self-released around that time. This was all prior to him being signed to a major record label and releasing his first full studio album, + (Plus).

Image copyright Getty Images Image caption A fresh-faced Ed Sheeran back in 2011, after No. 5 had been released

"Number five was a concept idea," Jake Gosling, the EP's producer, tells Radio 1 Newsbeat.

"We wanted to make songs that weren't your standard 'Ed songs'. I was working with Wiley at the time and we looked at sorting collaborations with artists in the grime genre."

There are eight tracks, each bursting with honest and personal lyrics.

Track one - Lately - features Devlin rapping about insomnia: "Overtired, pale-faced like Michael Myers. Bags underneath my eyes can show the baggage I've acquired."

On You, Wiley raps about his grandmother: "I'm 31 now, I'm still saying 'Yes nan'. You had to replace my mum, dad... two parents in one."

Image copyright Getty Images Image caption Ed Sheeran and Wiley at the 2017 Q Awards

Track five, Little Lady, is perhaps the most difficult to listen to, with a heartbreaking story at its centre.

With verses from Mikill Pane, it's a reworking of The A-Team, and tells the story of a young girl, forced into sex work and eventually murdered by her pimp.

"Little lady, you're trembling with fear. Your skinny frame kinda resembles a deer," he raps.

Mikill Pane met Ed in a clothes shop on London's Oxford Street.

They became mates, gigged together and discussed Little Lady as they walked to the house where the singer was staying.

"I told him I'd written these lyrics when I was a lot younger... years before I met him," he tells Radio 1 Newsbeat.

"I rapped them for him and he decided there and then we should do a remix to The A Team and call it Little Lady.

"At first I wasn't even meant to be on the record. He only wanted his grime heroes on that EP. It was nice to sneak on to what would become a classic."

Image copyright Getty Images Image caption Mikill Pane says - unlike some of the artists on No. 5 - Ed hadn't heard of him before they met

Mikill says Ed wanted to touch upon the "more sensitive side of a lot of these grime MCs".

"It worked," he says, as well as impressing with his fusion of musical styles.

"Ed's ability to shift between his folk songs and then a Gyptian cover or 50 Cent cover or a Tinie Tempah cover was remarkable. No-one else was doing it."

"Ed was perceived as a singer-songwriter," says Jake Gosling. "But he loved rap music and it showed a different side to what he was doing. It opened up the doors to a completely different scene."

Behind the scenes, Jake reveals the pair worked to a tight deadline, so it wasn't always possible to get Ed and the collaborator in the same room.

"It was pretty fluid," he says. "There wasn't too much external pressure so we just got on with it. But it was quite hard to pin everyone down."

Jake thinks the EP, which charted at number 46 in the UK Album Chart, helped elevate Ed's profile and lead to his subsequent success.

"We didn't have a record label, it went out on (digital music distribution platform) Tune Core and it was charting. The rest is the rest. It leveraged the whole situation into Ed signing a record deal and becoming the artist he is today."

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