Dave Gilmour, Royal Festival Hall, London

While his guitar gently weeps

Here's a concept even weirder than Arthur Smith sings Leonard Cohen: David Gilmour sings Bizet. A high spot of the legendary Pink Floyd guitarist's Friday night RFH extravaganza – part of the Meltdown 2001 festival, devised by Robert Wyatt – was his rendering of a rapturous aria from The Pearl Fishers. In French. And in a high tenor that became a climactic falsetto. Charles Trenet meets Aled Jones. It was gorgeous, but scarcely what the fortysomething Floydies in the audience were expecting.

Gilmour took the stage in his rock-star-millionaire garb of nondescript T-shirt and jeans and the demeanour of a truculent roadie, picked up an acoustic guitar and launched into a one-man-band version of "Shine On You Crazy Diamond", his tribute to the damaged visionary Syd Barrett from the original Floyd line-up. As the stage filled up with instrumentalists – saxophone, double bass, cello, piano, second guitar, and (count 'em) nine backing singers – we realised his wasn't going to be an MTV "Unplugged" session. It was a showcase, by a musician bored with his rock-god pigeonhole, of his eclectic musical taste.

Gilmour raided the band's back pages for favourite moments – "Fat Old Sun" from Atom Heart Mother, "Wish You Were Here" in a gorgeous duet with Neil McColl, "Comfortably Numb" from The Wall (with a contribution from the Robert Wyatt, who now resembles Moondog). He threw in Richard Thompson's folksy "Dimming of the Day" with the delicacy of a Celtic harpist. Ignoring the over-familiar Dark Side of the Moon, he sang three numbers from The Division Bell, calming the rock'n'roll strut of "Coming Back to Life" into a tender tribute to his wife, Polly.

When he finally strapped on a Stratocaster, the audience whistled and yelled for the authentic Gilmour sound – those liquidly stratospheric electric solos, at least an octave higher than anybody else's. Visibly, he relaxed with an axe. But the revelation of the evening was the romanticism of his arrangements, the mellifluousness of his voice, the churchy swoop of the streaming, arpeggiated cello and the nine-part choral harmonies. Is that the sound this burly guitar hero has secretly craved?

The audience cat-called genially throughout, like adolescents cheeking the headmaster at Gilmour High. "Where's Roger Waters?" asked a Floyd anorak of the departed bassist. "You want him, you can have him," said Gilmour. He closed with an electric reprise of "Crazy Diamond", returned for a full-stage epic blast of "A Great Day For Freedom", and sent the audience home to bed with a lullaby called "Hushabye Mountain". The big softie.