Britney slips back into Toxic nude bodysuit a decade on for Vegas rehearsals... but has she used make-up trickery to get that six-pack?

Britney Spears is seen here in a stunning array of costumes during her final dress rehearsal for her Las Vegas show - which kicks off tonight.

The 32-year-old singer and mother-of-two is in fantastic shape; clearly the graft and rigour of the past few months have paid off as she gears up for a two-year Piece Of Me residency at Planet Hollywood.

In one particular outfit - a nude bodysuit which appears to be very much inspired by her 2004 Toxic music video attire - Britney is even sporting a six-pack.

But a decade on, it seems the Princess Of Pop might have opted for a spot of make-up trickery to give her abdominals that extra Vegas showgirl quality.

Back with a bang: Britney Spears is seen here doing her last dress rehearsal on Thursday ahead of the opening night of her Las Vegas residency Piece Of Me on Friday at Planet Hollywood

Looking good: The 32-year-old star is seen here in a nude bodysuit, evocative of the one she wore in her 2004 video Toxic 

Make-up contouring: The mother-of-two is looking in great shape, but seems to have got a little extra help with some clever make-up trickery to create the illusion of a six-pack

Known as contouring, make-up artists have all kinds of tricks up their sleeve to target various areas of the body to create slimming or shaping effects using clever airbrush techniques.

Flashback: Britney in 2004 music video Toxic

It's an oft used trick of VIPs who want to achieve that camera-ready look.

And while Britney's months of rehearsals have clearly toned and sculpted her body, it's quite quite possible that she is also getting by with a little help from her friends.

On Thursday, the day after Christmas, Britney was putting herself through her paces one last time.

Seen here in a series of pictures, it's apparent she has pulled out the stops in the costume stakes.

There are corsets, bikinis, sheer numbers and an array of other stomach and leg baring ensembles.

Throw into that wigs, an angel costume worn as she is lowered from the roof and of course that iconic Britney headset microphone (with those dance routines, holding one would be tricky).

Britney gave a hint of nerves on Thursday, tweeting a message to her fans along with a couple of snaps.

'I've got chills,' she wrote. 'Last dress rehearsal for friends and family before opening night tmw. #1DayTillShowtime.' 

She will perform over four nights starting on Friday night before taking a month-long break. She will then return to the stage for a month of shows beginning at the end of January.

Britney will perform 24 of her hits each night and she has made sure to include many old favourites for her fans.