"Using shades of lead, you can manipulate and create an illusion of color," says Okafor.
Each image takes the artist an impressive 100 hours to create, from either photographs or acquiescent friends and family positioned as life models.
"Before I start to draw I usually spend a few days analyzing the person or structure. It's important that they feel comfortable so you can get their natural expressions," he says.
Such is the dedication to a piece that it's not uncommon for him to dream of it: "but the thing about that", he told CNN, "is it allows me to draw from memory."
Okafor's growing list of celebrities drawn in lifelike realism include Rihanna, Beyoncé
, Hollywood actress Zoe Saldana, singer Adele, as well as world figures such as Mother Teresa and President Obama.
'Art was never encouraged'
His latest portraits, titled "Interlude," a series of images of women with their eyes closed, explore moments of quiet contemplation.
"Our technology age -- as amazing as it is -- it's very distracting, everyone has their [cell phones] glued to their hands," says Okafor. "It's about having that moment to yourself."
Each of his subjects are drawn in full frame and in side profile to capture an inner "radiance."
Born and raised in London to Nigerian parents, Okafor's fascination for drawing with pencils began at eight years old. A career in art was not something encouraged by his parents.
Although sympathetic, "my parents were very much about us coming to this country [the UK] to pursue an academic career, mathematics, or law -- they thought that might be more lucrative."
But after graduating from college in 2009, friends suggested he share his drawings on Facebook. "I joined out of interest and I started to show my work on a few websites and before I knew it I'd acquired a following," he says.
His work's capacity to be appreciated around the world led to a Threadneedle Prize exhibition in 2012 at Mall Galleries, based in London.
At the time the British-Nigerian artist was the youngest to showcase. Subsequent curatorial and solo shows soon followed as well as an army of more than 100,000 fans on Instagram
. And back in 2013, Okafor's portrait of the late King Hussein of Jordan was presented to his widow, Queen Noor.
"I've [been] so overwhelmed by everything," reflects Okafor. "It's quite surreal for me whenever I think about it." Today, his works can fetch up to £20,000 [$25,000] depending on the size.
His devotion to the most ubiquitous of writing tools led to an invitation by his favorite pencil manufacturer to see them produced in Germany.
"Along this journey I've ticked off so many things I want to do and most importantly being able to inspire others. I go into schools and I teach kids how to draw now and that's what's so important to me," says the fine arts graduate, who hopes to stretch his subject matter further. "I've always drawn people but I hope to do more landscapes and nature."