Jacob Collier is sitting cross-legged on a stool in the back room of his mum's house in north London. But this is no ordinary back room, as anyone who has checked out In My Room, the young Londoner's utterly original debut album, will attest. Strewn about him on the floor, hanging from the ceiling, stuffed on to shelves or crammed into boxes and baskets, is a vast trove of musical instruments: keyboards, guitars, double basses, tambourines, cymbals, tablas, melodicas and other, less immediately identifiable noise-making objects.

It was from this modestly proportioned room in December 2011, at the age of 17, that Collier began posting his now legendary YouTube videos, astonishing multi-layered creations in which he plays every instrument, sings every harmony, and cuts it all together into split-screen videos that have caught the imagination of musicians and civilians around the world.

“This room has been my playground for 22 years,” says Collier surveying the mess around him, “and for my first album, I think it was very important for me to frame this magical world that I have been playing in.”

A self-confessed introvert, Collier would spend days on end in his room, patiently crafting his videos, sometimes involving as many as 350 layers. The results are so ridiculously impressive that Collier was inevitably tagged with words like “prodigy”, “genius”, and “sensation”. So, was he born with some kind of innate talent, or was he just raised in a very fertile musical environment?

“It has to be a mixture,” he says emphatically. “The way my brain works, it created me thirsty. From the off, I was a sponge for information that had emotional connotations, I think that was it. I was brought up to see the world as emotional, and anything that I could get my hands on that helped me explore that emotional stuff, I was fascinated by.”

His mother Suzie is a violin teacher, and from before he could speak, Jacob was sitting on her lap during her lessons, quietly absorbing every note.

“Really, I was brought up with music as a second language. My mother was extremely encouraging of the sensitivities of my brain. It was this sense of curiosity but never pressure. My eyes were opened, and my emotional mind was opened to things that weren’t completely normal but made utter sense to me. It was like ‘this is Bach, this is Stevie Wonder, this is Earth Wind and Fire, just enjoy it and walk into it’.”

In contrast to the conventional narrative of the prodigy – of the lonely, hot-housed child practising while his peers play football outside the window – there was never any pressure to practise or to study music.

“There really wasn’t, and it surprises people,” he says. “Parents write to me, or come up to me after shows and ask me ‘How can we get our children to be as excited as you obviously were as a child?’ It’s not necessarily what they want to hear when I say, ‘Don’t make them practise!’”

By the age of seven he had already taught himself to play a variety of instruments, and the multi-track technology allowing him to play along with himself was just an obvious next step.

“I was given this music programme called Cubase, one of the first multi-layering programmes, when I was seven, and I graduated to Logica at 11, and that became my primary instrument. I would listen to tracks by Stevie Wonder, and I would ask ‘what’s the bass doing? What are the drums doing?’ I’d listen to those things, and then I would recreate them.”

Wonder, another musical polymath, is a constant source of inspiration, and the most watched of Collier's early videos are his smile-inducing versions of Isn't She Lovely and Don't You Worry 'Bout a Thing.

“Stevie was, and maybe still is, my number one music hero,” he enthuses. “Not only did Stevie do this impossible thing by bridging the gap between the rich complexities of harmony and the simplicity of the song, but he also exudes this sense of joy. The joy of that music was so loud to me, it just made me jump up and down.”

Over the last four years, Collier’s videos have clocked up about eight million views, attracting particular admiration from other musicians, among them front rank jazz musicians like Chick Corea and Pat Metheny. Quincy Jones, producer of some of the biggest hits in music history, was impressed enough to sign Collier to his management company, which is how, late last year, the young man found himself in LA, unveiling his new record to Jones and his best friend, Herbie Hancock. Was it an intimidating moment?

“It’s hard to put into words. It’s that interesting thing, when you have a song that you love and then you play it to someone else, and you hear it through their ears. To be lent those particular ears was beyond special.”

Also last year, Collier hooked up with Ben Bloomberg, a sound designer at the Media Lab in MIT, and together they have designed a rig that transfers Collier’s multi-tracking approach to a live performance, using multiple loops and innovative video technology, which he will be unveiling tonight at the Cork Jazz Festival.

The transition from geeky kid tinkering in his mother’s back room to international touring musician and friend of Herbie Hancock has been so swift, Collier is still living at home, still making music in his mother’s back room. So can he imagine ever leaving it behind?

“I have been thinking about this recently because I’m going to be travelling a lot. I am unlikely to be home for more than a month in the next five years. But it’s always a very special thing to be at home, to be in this room, and to be Jacob. In a way, emptying the dishwasher is more life affirming than a queue of adoring fans.”

Jacob Collier opens the Guinness Cork Jazz Festival tonight at the Everyman Theatre. guinnessjazzfestival.com