Pharrell Williams ''lost a bet'' with his friend when he created his Chanel-Pharrell capsule collection.

The 45-year-old singer created an exclusive unisex capsule range for the prestigious French label alongside its late creative director Karl Lagerfeld - who passed away last month at the age of 85 - and the venture meant he had to buy his pal an expensive watch because his unnamed buddy had always predicted he'd work with the designer.

He said: ''It's kind of surreal for me because a buddy of mine said to me, you know one day you're going to end up working with them, you're going to make some stuff with them, I said 'Ah whatever, no I'm not'. Then he made me a bet, he said, 'Hey if you end up working with them you gotta buy me one of those watches.'

''At that time, gender fluidity wasn't as loud and pronounced as it is now, I just was doing it because it's what I want to wear, it's my thing. I love and celebrate individuality. I get invited to the house, the maison, I meet Karl and all these incredible women and ended up in the campaign, then the film, and now we have a campaign and another film. I lost the bet but it's a bet that I've been happy to lose.''

The 'Lemon' hitmaker was given the creative freedom to ''push'' the brand's ''heritage''for his limited edition collection.

Speaking behind-the-scenes in a video titled 'The Making Of The Chanel-Pharrell Capsule Collection', he said: ''Gabrielle Coco Chanel didn't see partitions, and it's interesting, because neither did the brand when it came to giving me a shot.

''[Chanel] is not afraid of these things, just like [Gabrielle] wasn't afraid. There doesn't need to be boundaries as long as you can hold onto the heritage and continue to push it, like Karl always [did]. We don't need walls, we need bridges.''

The Chanel-Pharrell collection will be available in select stores from April 4.