Strumming an acoustic guitar that dwarfed her delicate frame, stamping the floor like a latter-day Janis Joplin, plunging deep into the flagrant source of her soul, Ayo sang a song about being lonely. It was a bewitching performance of unheralded power. Admittedly, Ayo's mojo had already been working on me. About 18 months ago, news of the huge European success of her debut album Joyful managed to filter across the English Channel. Whispers were heard in London about a young, talented, mixed-race singer with a voice of fearless yet fragile soulfulness who was hitting it big in the French charts.
Next it was America's turn, with appearances on prime-time TV and endorsements from America's showbiz aristocracy. And earlier on the night of the Africa Express Koko gig, I'd managed to chat to Ayo. Her broad, generous smile, her funny unaffected banter, her ready intelligence and weightless innocence worked like sweet voodoo.
This sunny smile and generous innocence are the survivors of a difficult childhood in and around the German city of Cologne, where Ayo was born Joy Olasumnibo Ogumaki in 1980. Her Nigerian father and Romanian Gypsy mother provided a happy enough home for the first few years of her life, but when her mother hit the hard drugs, domestic bliss turned sour.
Ayo and her three elder siblings were shunted from care home to foster family to their father's house and back again in a nightmarish round of trauma and betrayal. She has memories of her father weeping at the care home where the German social services had forced her and her sister to go at the age of six, and of having to hand back Christmas presents to the police because they'd been stolen by her junkie mother. Then there was the challenge of surviving as a black kid in a very white land.
"Everything I experienced in Germany made me stronger," Ayo tells me. "We were never in one place for too long. I became isolated. I focused on my family, my father and all the problems. And my dreams...."
Ayo's trust was blighted by her mother's addiction, so she had to rely on instinct when record labels came knocking. She rejected proposals to turn her into a reggae diva, or a counterfeit Beyoncé, and left for London and Paris to carve out success.
"I didn't know exactly what I wanted, but I knew what I didn't want. Whenever I felt that something wasn't right for me, I just didn't do it," she remembers. When the boss of Polydor in France, Jean-Philippe Allard, heard her plea and gave the then pregnant Ayo carte blanche to record the album she wanted, it came like a moment of redemption.
Joyful went double platinum in France and other European countries, appealing thanks to its candour, its gentle acoustic simplicity and its easy rhythms. Ayo was hailed as the new Sade or Europe's answer to Corinne Bailey Rae. But her music is more bruised, more defiantly open and uncompromising. It's the mix of sweet, fragile soul and discomfiting honesty that has become Ayo's strength and signature, and it is evident on her new album Gravity At Last.
"When I started writing my music, it helped me so much. I stopped being embarrassed," Ayo recollects. "Telling the truth in my songs became almost like a drug. It was important for me to get rid of it, because it was like a weight on my chest. I didn't really communicate with my parents at all when I was making Joyful. So I guess I found a way to communicate with my music. I just felt like, they're going to listen to that, because they have to!"
When Ayo's father eventually listened to his daughter's debut CD, he must have felt blessed by what he heard, especially the song "Without You", in which Ayo thanks him for his courage and protection. This generous response to her dark past is typical. Where you might expect only bitterness, venom and anger, Ayo delivers wisdom, compassion and a defiantly positive outlook on life.
Ayo's son Nile came into the world simultaneously with the runaway success of Joyful. For her, these two pieces of good fortune are inextricably linked. Ayo often alludes to her need to function, which kept her sane through the darkest corridors of her life. Nile now embodies that need. "When I look at my son, it's like I'm facing myself. It's like... OK, this is why I'm here. He always gives me so much strength. He's my gravity actually."
Ayo offers a jaded world the splintered blues of Billie Holiday, with a funky, jazzy, reggae coating as functional and pared down as the emotion in the songs themselves. Her instinct must have told her that an uncompromising desire to tell the truth in her songs, to confront demons, is the key to success and the secret to the perfect bittersweet balance of her music. Her courage makes Ayo a mesmerising presence, a fighter who has found gravity at last.
'Gravity At Last' is out now on Wrasse Records. Ayo performs at the ICA in London on 20 April