ZZ Top, Brixton Academy, London<br></br>Martina Topley-Bird, Scala, London

Blame it on the boogie

It was a stroke of genius, when you think about it. Call it the Clive Dunn Factor, if you will. When Billy Gibbons and Dusty Hill decided, a quarter of a century ago, to make themselves look like old men, they ensured that by the time they eventually did become old men - ie now (they're 53) - nobody would have noticed them age in the slightest. Tonight, with berets jammed down over their brows, cheap sunglasses hiding their eyes and face-fuzz obscuring the rest of their features, they might have stepped out of any year in the last two decades (the only concession to modernity is a pair of holographic guitar straps). For all we know, they could even be a tribute act: their anonymity is such that they might as well be called ZZ 1 and ZZ 2.

Rock'n'roll folklore has it that Hill and Gibbons, during a hiatus in 1979, both independently grew their trademark Santa Claus/ Osama Bin Laden beards without the other one knowing. This kind of telepathy has served them well. Their comical appearance means that the slightest choreographed visual gag - a double hand jive, a knee-knocking Charleston, a coordinated finger-point - brings the house down.

In the Eighties, I could never have imagined myself attending a ZZ Top concert. Back then, they were one of those big Reaganite rock bands, like Dire Straits, Queen and Springsteen (subtext schmubtext, he knew which side his bread was buttered), and the multi-platinum-selling Eliminator was one of those big Reaganite rock albums. With the passing of time, though, Eliminator rocks like a mutha, and those bands don't seem like the enemy any more (well, OK, Dire Straits are still the enemy).

In retrospect, ZZ Top now seem like a less hip White Stripes (but almost as affecting on a gut, or perhaps that should be ass level): a minimalist blues-rock outfit who just roll up onstage with the minimum of fuss, and zero in the way of help (I don't know what I expected - a 40 piece big band? - but it really is just the three of them).

There is something almost physically irresistible about ZZ Top's locomotive boogie, located somewhere in the interplay between Gibbons' parched vocals and silvery, top-string riffing (on many songs, he's soloing from the word go), and Hill's deceptively casual basslines. There aren't many acts who could get 2,000 people punching the air and chanting "I got a girl/ She lives on the hill/ She won't do it but her sister will" to a song most of us have never heard before.

The third member, of course, is drummer Frank Beard. A friend of mine has developed the concept of "a Frank Beard", meaning a piece of trivia which everybody knows, but thinks they are alone in knowing (the original being "Did you know that the only member of ZZ Top without a beard is called... Frank Beard?!). There is little else to say about the moustachioed sticksman, apart from the fact that his clean-shaven chin makes him look older than his two frontmen, and that his metronomic hi-hat beat is the unaccredited driving force behind the band's souped-up sound.

It's as well that ZZ Top are rock stars. Having committed themselves to terminal unshaggability with their Amish/ hillbilly facial hair, in any other walk of life, their Nebuchadnezzar neckwarmers would have committed themselves to lifelong virginity. Every girl may be crazy 'bout a sharp-dressed man, but only if he's had a quick once-over with a Gillette Mach 3. Happily, this is not a problem. ZZ Top could keep on keepin' on until the bison come home, have a shower, get changed, and go back out to do whatever it is that bison do.

They save the best till last, in the shape of an Eliminator double-header. First up is the mean-assed motor-boogie of "Sharp Dressed Man", featuring one of my favourite moments in pop: "Silk suit, black tie..." sings Gibbons, before Hill, in a ludicrously deep film trailer voice, interjects "BLACK TIE". When they strap on a pair of fluffy white guitars for "Legs", I suddenly realise who they've been reminding me of all along. They're the Honey Monster, and when the Sugar Puffs people get them together for the inevitable collaboration, I demand my 20 per cent. Tell 'em about the boogie, mummy...

Stepping out for the encores in rhinestone-encrusted stetsons and waistcoats, Hill takes the mic and says "Theng Yew" in an authentic Texan drawl. This is the man who, in 1985, blasted himself in the stomach with a shotgun. How much more authentically Texan do you want?

When Martina Topley-Bird made her first fateful encounter with Tricky, she was a mere schoolgirl, and went on to become his muse and partner-in-rhyme over several excellent albums, most notably the classic, mould-breaking Maxinquaye (hers are the Estuary English tones you can hear all over the likes of "Black Steel In The Hour Of Chaos"). Her debut solo album, Quixotic, has just been released, and it doesn't break any moulds whatsoever. Indeed, its sonic path, like the little boy following Good King Wenceslas through the snow, never steps outside the footprints of her mentor (and indeed Tricky turns up on a couple of tracks). Nevertheless, it has just been shortlisted for the Mercury Prize, and there's every chance Martina T-B will emerge victorious. One reason for this is the brain-crushing banality and asinine aversion to adventure of the judging panel. But another is perhaps the fact that there is a desire out there for this kind of record: put simply, Tricky without the weird stuff.

Not that she is a bad thing per se. Trip-hop cliches abound (she even uses that crackly 1940s microphone effect, à la beth Gibbons), but her slender, elegant presence is the very definition of nonchalant. In fact, I don't think I've ever seen a singer less... well, less chalant.

As her band and singers work up an unhurried, slow-building Staple Singers groove - because we don't need to be any place any time soon - one finds oneself contemplating her Mona Lisa half-smile (which never cracks, even once) and concluding that yes, you can see what Tricky saw.

s.price@independent.co.uk

Martina Topley-Bird: Queen's Square, Bristol (0115 912 9000), 25 August