Billboard Music Awards: Kelly Clarkson shows off her weightloss with plunging red frock on stage

By Kimberley Dadds

PUBLISHED: 04:07 EST, 21 May 2012 | UPDATED: 04:07 EST, 21 May 2012

She's been undergoing a gruelling training regime to get herself in shipshape ahead of her TV appearances this summer.

And the hard work has clearly paid off for Kelly Clarkson as she unveiled a thinner frame at the Billboard Music Awards last night.

The Since U Been Gone hitmaker looked stunning as she performed on stage in a plunging red frock.

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Lady in red: Kelly Clarkson revealed the fruits of her labour as she showed off thinner frame in plunging red frock at the Billboard Music Awards

Lady in red: Kelly Clarkson revealed the fruits of her labour as she showed off a thinner frame in plunging red frock at the Billboard Music Awards

Kelly, 29, displayed her new physique as she belted out her hits to the star-studded crowd at the MGM Grand Garden Arena.

She had plenty of skin on show on her top half, as the scarlet gown dropped to the floor.

Clarkson wore her make-up simple with a slick of lipgloss, while her hair was worn down and in waves for the special appearance.

Standing out: The singer debuted her track Darkside as she performed at the MGM Grand Garden Arena

Standing out: The singer debuted her track Darkside as she performed at the MGM Grand Garden Arena

Showing some skin: Kelly has been working hard in the gym a! nd showe d off her new look at the awards show

Showing some skin: Kelly has been working hard in the gym and showed off her new look at the awards show

She used the opportunity to debut her track Darkside, which will be the third song off of her latest album, Stronger.

The singer wrote on Twitter ahead of the performance: 'Just finished rehearsing for the Billboard Awards! Looking forward to performing my new single tomorrow for the show!'

Kelly has been spotted spending a lot more time in the gym recently as she gears up for a number of TV appearances.

Lavish set: Clarkson performed to the star-studded crowd at the event

Lavish set: Clarkson performed to the star-studded crowd at the event

Impressive vocals: She is set to appear on TV show Duets alongside Lionel Richie this summer

Impressive vocals: She is set to appear on TV show Duets alongside Lionel Richie this summer

She has been named as one of the stars of new ABC programme Duets, alongside Lionel Richie, Robin Thicke and Jennifer Nettles.

The American Idol star, a talent show alumni herself, has said of the programme: 'What first drew me to the whole idea of duets was the fact that it is completely different - in the sense that we get to actually collaborate with the artists that we choose.

'I think its really cool that we get to find talent that we really believe in and we get to perform with them and help mould someone into whatever they want to do with their career.'