Katherine Jenkins has always been desperate to play the good girl in public, even in the face of a drug scandal. But that, it seems, is a thing of the past.

The opera star has thrown caution - and her carefully cultivated clean-cut image - to the wind for her new 12-date tour, which kicked off at Birmingham's NIA last night.

The mezzo-soprano put on a rather racy display for the concert's opening act, taking fans by surprise as she descended from the roof in spectacular fashion with the help of a topless male dancer.

The high-wire stunts and incredible acrobatics are what music fans have come to expect from pop stars like Madonna and Pink, and now it appears Katherine wants in on the act.

Swing low: Katherine Jenkins puts on an acrobatic display on the opening night of her UK arena tour at the NIA in Birmingham last night

Flying high: The mezzo-soprano made in on to stage despite injuring her knee, but doctors had to give her an anti-inflammatory jab

The 29-year-old, who was a judge on the ITV show Popstar to Operastar, has given her wardrobe an overhauled, too.

Gone were her usual conservative ball gowns, turfed out in favour of fishnet stockings and a daring bustier.

But her vamped up image has come at a cost - she injured her knee while preparing for the physically demanding show.

Voluptuous: The singer looked stunning low-cut dress and fishnet tights

She hurt her leg during a work out and doctors were forced to give her an anti-inflammatory jab before she took to the stage.

Writing on her Twitter site on Tuesday, the 29-year-old gym fanatic reported: 'Urgh... I just had to have a steroid injection into my knee!

'Damaged it with my running and need to be in good shape for start of tour tomorrow!'

A friend was quoted as saying: 'It's about time Katherine cooled down the exercise. She's either in the gym or out running nearly every night.

'The injury caused her a lot of pain but there's no way she'd miss out on this tour.

'Katherine doesn't need to work out so hard she has a figure to die for and beautiful curves.'

The show must go on: There were fears the injury could have prevented Katherine from performing

The slender Welsh singer works hard to get her shapely figure and has been described by friends as a 'gym addict'.

Last year Katherine breezed through a 10k charity race with hardly a hair out of place to raise money for the Kidney Wales Foundation.

She also has a state-of-the-art treadmill installed in her home and is often seen running in the Welsh countryside.

But her lifestyle hasn't always been quite so healthy. In 2008, Katherine confessed that she experimented with class A drugs while studying at the Royal Academy of Music in the late 1990s.

She came clean because she worried it 'may all come back to haunt me' and has since described taking drugs as the biggest regret of her life.

Hitting the right note: The singer, who was a judge on Popstar to Operastar, stands centre stage in a floor-length ensemble