Britney Spears shows newfound confidence in a revealing bikini top

After a shaky start to her musical comeback last year, it finally looks like Britney Spears has got her self-confidence back.

Pictured rehearsing for her upcoming tour in a skimpy bikini top, it looks like the troubled singer has finally turned a corner.

As she writhes to the music in a Los Angeles rehearsal studio, Britney is cutting a very different figure to this time last year, when she was stretchered out of her home for psychiatric evaluation.

Looking good: Britney Spears looks in great shape as she rehearses in a Los Angeles studio

During her years out of the spotlight, Britney gained weight and stepped back from her career.

But after making her comeback last year and getting back in shape, Britney is slowly, but surely regaining confidence with her figure and performing abilities.

In exclusive pictures on her official website, Britney gives fans an insight into what they can expect on her upcoming The Circus: Starring Britney Spears tour.

Britney is set to begin her world tour in March, starting in her homestate of New Orleans.

The 44-date runs for four months and covers the U.S., Canada and London, with plans to expand to the rest of Europe.

Working it: Britney throws herself into the energetic routines

Britney will perform six gigs in London's O2 arena between 3-14 June.

So until then, Britney is working hard at the studio with her team of dancers and choreographers JaQuel Knight - who choreographed Beyonce Knowles's Single Ladies - and Tony Testa.

During her whirlwind trip to Europe in November, which saw her perform live on TV shows including The X Factor, Britney was criticised for her obvious miming and lacklustre dancing.

As well as her lip-synching on the episode of The X Factor, it also emerged that the singer hadn't spent any time with the contestants, who all sang live that night.

Lift me up: Britney is projected into the air by two burly male dancers

Enjoying the view: Britney sits in the middle of her dancers watching them strip off

While been taken as a snub, it later emerged that Britney felt 'too shy' to offer the hopefuls advice.

The same night, Britney was expected to perform at the G.A.Y. nightclub in London, but angered fans when she backed out.

The club's promoter, Jeremy Joseph, says: 'I don't know why she didn't go on. She's really shy, and obviously she didn't feel confident enough. I tried to persuade her, but she said no.'

Last month, her mother Lynne Spears admitted Britney wasn't the same confident superstar she was back in the early Noughties.

Bringing sexy back: Britney is looking healthy and toned again

She said: 'I think Britney’s happy in most ways - very happy with her kids and ecstatic about work. But there’s something missing in her life.

'That gut belief she had in herself when she was so young - that’s what’s missing, and she’s got to get that back. She could set the world on fire in those days, and she knew exactly what she wanted.

'But the hardships she’s been through have made her a little hesitant. She needs one big boost, one plug of energy and she’ll be there.'

After giving birth to two boys and her subsequent health troubles, Britney was out of shape for several years, but is now feeling good again after losing 20 pounds.

She told the January issue of Glamour magazine: 'I have had to work hard at getting [my body] back to where it used to be.

'I used to be obsessed with working out. But I can't get motivated right now because I'm so focused on my music.'