Dolly Parton's costume looks as though it was put on with a pneumatic pump and winches. A vision in electric blue and sequins, she teeters gamely on preposterous high heels. Her tiny waist is dwarfed by that famous bust, which actually seems to inflate along with her fearsome vocal chords. This is, of course, exactly the Dolly the crowd have paid up to £50 each to see. "It costs a lot of money to look this cheap!" she quips to shrieks of delight.
It is 19 years since Parton last toured in the UK, but she is a bigger icon than ever to country fans, pop fans, gay men, bra manufacturers and Dolly-ed up teenage girls who clearly find this Dumb Blonde, as her 1967 hit had it, more fun than Madonna. Effortlessly, Parton cajoles them into joining in on harmonies and roaring with "therapeutic" laughter. "I love you, Dolly!" someone shouts. Instantly Parton fires back: "I thought I told you to wait in the truck."
However, behind the cartoon persona is a complex and serious artist who is a mistress of the hard sell of top-drawer country-based music.
There is probably no other 56-year-old artist who relies so little on nostalgia. Give or take 1974's Jolene, her set is based around her last two albums - 2001's Grammy-grabbing Little Sparrow and this year's Halos and Horns - and like the recordings, it re-establishes her country credentials while sounding pop and relevant. However, her biggest asset is her common touch: she delivers her songs like stories told across the garden fence.
Dig beneath the kitsch and you find within Parton's music a well of pain. During Little Sparrow, you can hear a sequin drop as the zither-and-guitar-pickin' singer spells out a warning to women who might be "crushed" by men, although she brilliantly flits between tragedy and comedy. Detailing her poverty-stricken childhood, she explains that her parents had 12 kids by their early 30s was because they were "horny Baptists".
Her immaculate professionalism slips just once, when she introduces My Tennessee Mountain Home, about her late father. And perhaps, in that millisecond voice tremor, she reveals the person behind the persona, a special treat for those who love her. The affection is mutual, as she dedicates a surprisingly tear-jerking I Will Always Love You to cheering hordes who hurl flowers at her feet.
· At the Carling Apollo, London W6, tonight and tomorrow. Box office: 020-7344 4444. Then touring .