Well THAT makes a change! Alesha Dixon rejects tried and tested minidresses in favour of plunging trouser suit... as Amanda Holden shows some leg at BGT semi-finals

PUBLISHED: 20:14, 31 May 2013 | UPDATED: 22:31, 31 May 2013

She's settled for a tried and tested formula which has seen her parade her incredible pins in a series of super-short dresses at the Britain's Got Talent semi-finals to date.

But Alesha Dixon took her look in a whole new direction on Friday night as she covered up in a plunging black trouser suit.

And with the two female judges' roles seemingly reversed for the evening, Amanda Holden was the one to flash the flesh on stage in a sexy thigh-split number.

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Trading places: Alesha Dixon covered up in a plunging black trouser suit on Friday night's Britain's Got Talent live semi-final, while Amanda Holden flashed a fair amount of leg in a sexy red leather dress

Alesha Dixon rocks plunging trouser suit on Britain's Got Talent

Keeping her incredible figure relatively under wraps for the fourth live BGT semi-final, Alesha, 34, opted for a spot of power dressing in her chic and sophisticated ensemble.

However, the feisty singer made sure to add a racy element to the slightly conservative outfit by wearing her immaculately tailored suit with just a black bra underneath.

In addition to ditching her usual penchant for minidresses, the stunning starlet shunned the voluminous curls she has been sporting for much of the week in favour of a sleek bob.

Power suit: Keeping her incredible figure relatively under wraps for the fourth live BGT semi-final, Alesha, 34, opted for a spot of power dressing in her chic and sophisticated ensemble

Strutting their stuff: The two female BGT judges appeared to have traded places when it came to their sartorial choices, with Alesha having opted for tried and tested minidresses on three of the four shows this week

Alesha completed her look by adding height to her already statuesque frame with a pair of towering strappy gold stiletto heels.

Meanwhile, Amanda clearly fancied being the BGT vixen of choice for the evening, and looked positively incrediblE as she made a fierce style statement in a racy red leather dress by her favourite designer Jaton Couture, featuring a daring thigh-high split and a sexy mesh panel at the cleavage.

The mother-of-two completed her look with a pair of towering heels by Charlotte Olympia and jewellery by Mulberry and Annoushka, while wearing her ombre locks poker straight.

Some things never change: Show supremo Simon Cowell opted for his standard uniform of a navy blazer, a crisp white shirt and jeans

Hell for leather: Amanda's vampy dress featured a daring thigh-high split and a sexy mesh panel at the cleavage

Racy: The feisty singer made sure to add a racy element to the slightly conservative outfit by wearing her immaculately tailored suit with just a black bra underneath

Alesha and Amanda joined their male co-judges, Simon Cowell and David Walliams, on stage as they prepared to watch the BGT hopefuls battle it out in the fourth of five live semi-finals this week.

Thursday night's show saw vocal group Luminites and adorable Welsh dance troupe Pre Skool progress to the Britain's Got Talent final, which takes place on June 8.

Battling it out on Friday is vocal group Club Town Freaks, singers Alex Keirl and Asanda Jezile, impressionist Francine Lewis, illusionist James More, dance groups AJ & Chloe and Shockarellas, and solo dancer Poppin' Ron.