Hot Leg, Proud Galleries, London

I believe in a thing called Justin – and he's back

One day, when somebody finally tells the full, vertiginous story of the Darkness – the rise and fall of a great British rock band – it's gonna be the mother of all roller-coaster reads.

For now, all you need to know is that, after Justin Hakins had blown a reported £150,000 in three years on cocaine, they tried to make him go to rehab and he said, "Um, OK, you've probably got a point."

That was exactly two years ago. Since leaving the Priory – and the Darkness – Hawkins, now teetotal and clean, has been plotting in private, creating one-off MySpace follies in his home studio under a variety of partly or wholly fictional band identities. Eagle-eyed Justin-watchers online may have come across Barbecue Rock, Magnet Watch and Justin Hawkins' Panther, not to mention British Whale (who scored a hit with a Sparks cover during the Darkness days and released a World Cup song), Team Pig (the unreleased solo project which predates even the Darkness), and his Song for Europe runner-up with the duo Hawkins & Brown.

Hot Leg – it's the singular that makes it such a brilliant name, don't you think? – is the alias that's stuck. This time, Justin's assembled a real-life band, credited with "lead backing vocals", "lead bass", "lead drums", "lead" everything, which gives you some idea of the exuberance levels we're dealing with. If you thought Hawkins might come back cowed and apologetic, forget it. If you thought the second Darkness album was overloaded with Galileo-Galileo lunacy, wait till you hear Hot Leg's forthcoming debut. Their debut gig, however, in an impossibly rammed and sweaty Proud Gallery, is a more visceral experience altogether.

"Has anyone had their face melted yet by the guitar?" are his first words. From the off, Justin is out of the traps as if nothing's changed. Eyes wide and tongue lolling, within three songs he's exposed his tattooed torso, led a chant of "Man-rock! Man-rock!", and engaged in face-to-face riffing and general goofing-off with ... well, not his brother Dan any more, but new foil Pete Rinaldi. To see a born entertainer and shameless crowd-pleaser like Justin Hawkins on a stage again is an absolute joy.

Stripped of the studio insanity, much of the new material rocks, plain and simple. "You Can't Hurt Me Any More", "We Should Be Ashamed of Ourselves", "I've Met Jesus" (an old Team Pig song) and "Whichever Way You Wanna Do It" are every bit as rifftastic and hook-laden as, say, "Growing on Me". The epic "Trojan Guitar" may be read as an allegory for the Darkness's demise, if one chooses: "The enemy they befriended/They sacrificed our splendid plan to make a quick dollar ..."

The standout track in the Hot Leg repertoire, however, is "Gay in the 80s", a ripping Rinaldi-penned pomp-rock ode to the difficulties of coming out of the closet in a less tolerant age than ours, beginning with the a capella fanfare "Oh, in the Eighties, they weren't the Gay-ties ... They were the Straighties!"

There are a couple of eyebrow-raising covers: Jennifer Rush's "The Power of Love" performed with surprising sincerity (its "I'm your lady..." refrain unaltered) followed by Huey Lewis and the News's "The Power of Love", a theme apparently emerging. Everyone's waiting for Justin to go "Eye-eye-eye-eye feels like fire..." next, but the Frankie Goes to Hollywood song of that name is not forthcoming.

"I've been through a lot of changes in the last couple of years," Hawkins announces, returning for an encore in retro tennis gear. "I've had what you might call a breakdown..."

There's a nervous silence in the room, followed by a few sympathetic aaahs. Suddenly, the awkwardness is rent asunder by the riff that heralds a song which, it's not too premature to speculate, is an immortal rock classic. "I Believe in a Thing Called Love" doesn't merely reclaim the Darkness's legacy, or remind us that we're in the presence of a pop genius. It sets the skies – and thighs – on fire.