Big Brother star Sam poses in bikini

Sam, left, wore a long top and leggings for the Spongebob Square Pants 'The Sponge Who Could Fly' musical in March this year. She started her training regime in February

Sam Marchant, right, showed off her trimmer figure in a pink bikini while twin sister Amanda wore a blue swimsuit. They are the same size again after Sam shed a stone

Big Brother twin Sam Marchant has celebrated dropping a dress size by posing in a bikini for a photo shoot with her sister.

The 20-year-olds, who came joint second in the reality show two years ago, donned polka dot swimwear and high heels to show off their matching slender figures in the shoot for Closer magazine.

Slim Sam put on a stone in weight earlier this year, but thanks to a regime of healthy eating and exercise is now able to fit into the same clothes as her twin again.

She told the magazine: 'I went up a dress size - that doesn't sound like much, but for me it felt enormous. I had a muffin top that bulged over my jeans and Amanda's clothes were so much tighter on me.'

Although she accepts that ordinarily going up a dress size shouldn't be too upsetting, she said being a twin gives everything a different perspective.

'Every day I'd look at Amanda, who's a size 8, and it was a constant reminder of how I look when I'm at my best - not too skinny, just slim and toned.' Mail Online reported.