N.E.R.D, Corn Exchange, Edinburgh

It would be a whole lot easier to approve of US funk-rock entourage N.E.R.D if their lead singer and musical guiding light Pharrell Williams wasn't clearly in the midst of such a passionate love affair with himself.

An undoubted talent as a pop composer, frontman and sex symbol, Williams sadly hasn't learnt the lesson that a bit of humility can go a long way, even in the ego-powered world of rock'n'roll.

Comparisons between the last time the band played this venue and now should really have been an eye-opener. Then they took to the stage shortly after midnight on the evening the 2003 MTV Europe Music Awards were held in Edinburgh, with Justin Timberlake as guest vocalist and the Black Eyed Peas and Sean Paul providing special encore appearances. It was one of the finest live performances this critic has witnessed.

In 2008, however, the band have just released their third album Seeing Sounds to a merely modest fanfare, and this Edge festival gig was under capacity. Where once N.E.R.D were at least princes of the transatlantic pop scene's credible end, they now just make up the numbers for a more specialised, discerning audience.

It's a considerable stretch to think of them as an underground group (after all, the new album did go Top 10 in America, if barely Top 20 in the UK), but it's often the way that the less celebrated bands are the ones producing the most interesting music. For all their flaws, N.E.R.D delivered more than one moment of effortless pop brilliance throughout this show.

The most recent of these is the most brazenly odd, "Everyone Nose". One long, unashamed cocaine reference, its intensely catchy "all the girls standing in the line for the bathroom" chorus is accompanied by an army of girls personally plucked from the crowd by Williams.

Ah, yes, the girls. Singing the chorus line to "Run to the Sun", Williams enquires "how many of you girls want to come with me?" Affirmative whoops and cheers ensue. Of course, it could all just be an ironic comment on the rock star mythos but, if so, Williams overplays it.

That similarly cocky but musically impressive older favourites like "Lapdance" and "Rockstar" sit alongside a messy big interlude that introduces the sizeable band in cack-handed fashion demonstrates that more than one dichotomy exists within N.E.R.D.

At times you think you love them, at others you just want to escape to the bar and leave their bad chat-up lines far behind.