"I have the skin-tight black trousers," says Hayley Evetts.

"I only have a minute to get into them and it's quite a shoehorning job. There are four people who do the wigs and shoes, and one lady whose job is to help me put on my trousers - they are the priority."

When this former Pop Stars and Pop Idol favourite was growing up in Birmingham, she used to work in her mum's fancy dress shop "renting out Pink Lady costumes".

And when she was five, she would watch Olivia Newton John perform Summer Nights on Top Of The Pops, later falling asleep on her first trip to the cinema because she thought the ballad marked the end of the movie.

So Evetts is inevitably excited to be playing Sandy in the stage musical of Grease, a role she first took up in 2003 and returned to last summer.

"It sounds sad but, although I'm in the show, I can happily go home of a night and watch the DVD," she laughs. "I will never be sick of Grease."

Voted into the number one spot by viewers of Channel 4's 100 Greatest Musicals, this technicolour slice of Fifties' Americana premiered on Broadway six years before the John Travolta and Newton John movie.

"A lot of people think the stage show is going to be exactly like the film but it's not," says Evetts. "Although there are similarities in our performances.

Paul Manuel, who plays Danny, has got the John Travolta laugh down really well and he's there blow-drying his quiff every night."

As to Evetts' performance, if you're wondering whether she can match Newton John's entrance for You're The One That I Want, you might recall she is probably the only Pop Idol contestant ever to have received the compliment "sexy" from Simon Cowell.

"I was standing there on stage after I'd done Old Devil Called Love just thinking, 'come on, Simon, throw it at me' and he just came out with 'you are so sexy'," she laughs. "It was a bit 'urgh'. But at least he didn't slate me."

7.45pm tonight - times vary. Tickets cost £19-£30.50, call 01273 606650.

Ten things you didn't know about Grease:

Grease is probably the only hit Broadway musical to have been composed entirely on guitar.

Warren Casey started to write the script when he was made redundant from his job as a shop manager. The girl's pyjama party was the first scene he wrote.

The first ever staging was done with a budget of $171 and played to just 120 people. The run was immediately extended.

In 1973 the first London production of Grease featured a then unknown Richard Gere as Danny Zuko.

The 1978 movie version of Grease holds the record for "more concessions sold" than any other film in motion picture history.

Olivia Newton John and John Travolta were at Number One for nine weeks with You're The One That I Want, followed by a seven-week stint with Summer Nights.

Co-writer Jim Jacobs based Danny Zuko on someone he'd known at high school in Chicago.

The title Grease is a reference to the slick hairstyles, fatty fast food and oily custom cars of the period.

Grease is the longest running show in Broadway history.