BACKSTAGE at any concert is always a high-pressure environment.

At Alicia Keys’ performance at Nimes, in the south of France, a whole world of catering, crew and costumes intersect with the clock ticking down to stage time.

In a not-so-glamorous portable container, Keys is in glamour mode.

Her make-up artist has just left and Keys is finishing the job herself.

“I do my own make-up at festivals,” Keys admits, juggling eyeliner. “You’d be surprised how much this all costs.”

Her As I Am world tour is the biggest live production she has undertaken – in arenas and at festivals including Australia’s A Day On The Green winery circuit.

It is a touring luxury you can indulge when you’re an artist who still sells copious quantities of albums; As I Am debuted at No.1 in the US with nearly 750,000 first-week sales.

The Nimes show is stripped down by her standards, but still includes a revolving piano and a huge band who bring Keys’ three hit albums to life.

With Keys, a musician who happens to be a pop star, there’s plenty of freedom – her Prince cover How Come You Don’t Call Me Anymore runs for nearly 20 minutes with each band member getting the obligatory introduction and solo.

Success has seen her move from Prince fan to Prince friend.

“I love Prince,’’ she says, looking in the mirror – it’s like interviewing a hairdresser while they’re on the job.