Mary J Blige, Wembley Arena, London<br></br>Gonzales, Scala, London

The ghetto - it's just a state of mind...

Something very bad happened to Mary J Blige once, right here, in London. She won't tell us what it is, but alludes to it cryptically, and tonight she wants to thank the people of London themselves for helping her through it.

What can it be? I scan my mental microfiche for yellowing tabloid front pages. Overdose? Miscarriage? Firearms charge? Minor bitchslapping incident in the Met Bar? A little research reveals that during her first UK shows in 1993, she was booed offstage by a London crowd miffed at paying concert ticket prices for a mere six-song "personal appearance".

Hardly the worst thing that can happen to a Queen Of Hip-Hop Soul with five platinum albums under her Gucci belt, and after a decade of unparalleled success and worldwide acclaim, you'd think she might have got over it. But then Mary J is more sensitive than your average diva. Her cocaine problem and the break-up of her intense relationship with K-Ci Hailey of Jodeci – traumas which most celebrities might brush off (or get a manservant to do so) – affected Blige deeply enough to inspire not just a song or two, but a whole album.

In addition, she still bears the scars of a rough Yonkers, NYC childhood (literally: there's a mark under her left eye that she refuses to discuss).

It's this emotional vulnerability – and, it transpires, volatility – which will elevate tonight's show above the merely robotic. When she steps out in – by her uber-glam standards – a subdued outfit of jeans, vest and a compact disc hanging from each ear, and rattles through her early hit "All Night Long", I'm expecting a standard R&B-show-by-numbers.

And for a while, that's how it is. Quite why, having worked with the world's greatest producers – Dre, Jam & Lewis, Missy and the Neptunes – to create her excellent No More Drama album, she's chosen to use a nine-piece band who, despite the potential for spontaneity, paradoxically end up sounding like every other funk troupe you've ever seen, is a mystery (although, to be fair, they make a decent fist of the staggering single "Family Affair").

She skips effortlessly through hits like "Be Happy" and "I'm Goin' Down", her incredible voice – keening, high yet abrasive, reminiscent of Chaka Khan and Randy Crawford at their peak – cutting through the muddy sound. When she speaks, it's only in platitudes ("I don't need money to be who I am, I'm Mary J, all day every day"), and she's depressingly chuffed that "So many celebrities! Sting! The fashion designer Stella McCartney! Trevor Nelson! And my main woman, 'Sweet dreams are made of this...'" are in the house, but then so, equally depressingly, is the house itself.

Showing off her vocal range, she sings elongated covers of Marvin and Diana's "You Are Everything" and Philip Bailey's "Children Of The Ghetto". "I'm a child of the ghetto my-se-e-e-elf," she wails towards the end of the latter, by now kitted out in a red Zorro shirt and a sequinned trilby. "The ghetto ain't out there," she explains, indicating the leafy suburb of Wembley. "It's in here," she points to her own head.

Thus begins an emotional trickle that will soon become a flood.

A few minutes later, something remarkable occurs.

Freestyling at the end of a song, she begins to scream, addressing her own father. "I only wanted to meet my daddy... Where were you? Where were you?" She jumps around the stage violently, as though stamping recently-exorcised demons to death.

Calming down only slightly, she breaks into a rambling, intermittently coherent speech about how "Everybody only wants money," referring to problems with "drugs and abuse", and tracing them to the fact that "my parents weren't there to treat me right".

This isn't your average soul star's bland "The children are the most important thing in the world" speech, although she does end with those exact words. She wipes her eyes, apologises, sings (irony of ironies) "Not Gon' Cry", and wanders offstage. When she re-emerges in a rhinestone-encrusted white suit for "No More Drama", it's as though nothing had happened. But it had, and I saw it, right here, in London.

Is Chilly Gonzales taking the pith? As he and female co-rapper Feist shuffle out in It Ain't Half Hot, Mum helmets, you could be forgiven for cynicism, especially when the king of "prankster rap" proceeds to play an instrumental house track on a junior school melodica, complete with a length of pipe so that he can see what his fingers are doing (I know he has a song called "Futuristic Ain't Shit To Me", but I never expected him to get this lo-fi).

It turns out he's being coy with us. Sitting down at a piano, he then plays what I am reliably informed is five minutes of extremely complex Debussy. He will later pretend to have thought up "The Dance of the Sugar Plum Fairy" off the top of his head, and devote a track to eulogising Salieri (when it comes to the classical, Chilly knows his shit). But not before he's barely even pretended to rap "Political Platform Shoes" live, turning bad lipsynching into a Dadaist statement.

At last, he whips off the Daktari gear to reveal a hot pink suit – a cartoon Canadian gigolo – and the show begins in earnest. Chilly Gonzales, officially 33 (but more likely 40 if he's a day), has the deadpan, tragicomic face of Tommy Cooper, or maybe Ben Stiller 10 years down the line, and the biggest sideys I've seen on the face of a non-orthodox Jew since the Seventies heyday of Marty Feldman. Whipping a giant comedy plastic comb from a pocket, he slicks saliva through his hair like a low-rent Travolta, and gyrates his way through "Take Me To Broadway", his disco-sleaze anthem.

The self-styled "Entertainist" (he makes contemptuous air-quote marks around the word tonight) feigns indifference to his role as crowdpleaser – "I love the crowd, I hate the crowd, I constantly constipate the crowd... I want to be loved and hated in equal amounts" – but there's no question that he's having a sperm whale of a time up there. So much so, in fact, that he'll perform "Broadway" three times in total, at one point stripping to the waist to reveal a fat chain and, to coincide with the line "When I get there/I'm gonna show my chest hair", a surprisingly less-than-luxuriant thatch. The explanation quickly becomes clear: he encourages girls in the front row to pluck him.

In full flow – "So Called Party Over There", "You Snooze You Lose" – he's a spellbinding rhymespinner, and his beats are the work of, if not quite a Dr Dre, then at least a junior nurse. Authenticity and wigga-dom are not an issue here. Surrealism, not realism is his stock-in-trade: he twice claims to have "an extra testicle", and repeatedly refers to others as "figga" (his made-up alternative to "nigga").

Slipping into a hideous Noel Coward dressing gown, he sits back at the piano and turns Daft Punk's "Too Long" into something one might mistake for Nilsson.

Rising to accept the applause, he lights a huge Cuban cigar which, in a shower of sparks and cinders, turns out to be a Roman candle – now that's entertainment – and informs us that he's running for president, setting off on a victorious walkabout.

The people of France have been suckered for less.

s.price@independent.co.uk

Mary J Blige's new single, 'No More Drama', is released on MCA records tomorrow. Gonzales's album, 'Presidential Suite' (Kitty-Yo) is out now