Warming up for Bruno Mars seems like a slightly anticlimactic way for OutKast to play their first UK dates in 13 years. At their peak, the Atlanta duo operated like a sovereign nation within hip-hop, following their own powerfully eccentric vision. They bowed out of touring too early and, although nobody sounds like them, many rappers have built on their innovations. As André 3000 drily remarks, he used to get flak for singing: "Now every rapper sings. It's amazing."
Within seconds of the funkadelic thunder of BOB (Bombs Over Baghdad), it's clear they're undiminished by the hiatus. Their eight-strong band has the weighty intensity of Public Enemy and the wild elation of Sly and the Family Stone. André 3000, in a black jumpsuit with "I've Never Been to Afrika" on the front and a platinum wig, can perform Protoype with a handkerchief on his head or do press-ups on the monitor and still be, in the words of ATLiens, "cooler than a polar bear's toenails". Big Boi, more traditional with his baseball cap and medallion, performs increasingly goofy dance steps.
As personalities and as MCs they click like Lego, swapping rhymes at dizzying speed, and they make it look easy: playful virtuosos who introduce songs with daft jokes, converse in gobbledegook ("We have our own language, y'all") and rarely stop grinning. Their charm is as extraordinary as their skill, and backed by a phalanx of dancers chosen from the crowd, Hey Ya! is as joyous a communal moment as you'll find all summer. The only conceivable complaint is that they've wasted 13 years not doing what they do so brilliantly.
In stark contrast to the imposing narcissism of Wireless festival's Friday- and Saturday-night headliner Kanye West, Bruno Mars is so ingratiating that he does everything short of give each audience member a back rub. A shameless cornball in a Hawaiian shirt and white hat, he shuffles through genres (Motown, disco, reggae) and other people's hits (from Led Zeppelin to R Kelly) like a wedding DJ, or Jamiroquai's iPod. He's got a serious budget, too: final song Gorilla is armed with lasers, fireworks and flame jets.
Mars is inarguably entertaining, keeping the crowd singing and dancing all the way to the back of the park, but the 28-year-old seems more old-fashioned than the duo who are celebrating 20 years together. He's just an exceptionally slick song-and-dance man. Outkast, now as ever, are in a class of their own.
