Made In Chelsea's Tiffany Watson shows off her washboard abs as she poses in Calvin Klein underwear after workout with sister Lucy

She's a devoted convert to exercise and healthy eating.

And Tiffany Watson wasn't afraid to show off the fruits of her labour over the weekend as she posed in her underwear in a racy Instagram snap. 

The Made In Chelsea star, 22, displayed her washboard abs and toned legs in a black Calvin Klein sports bra and matching briefs as she snapped a selfie in front of her bedroom mirror. 

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Hard work pays off: Made In Chelsea's Tiffany Watson showed off the results of her hard work in the gym as she posed in Calvin Klein underwear over the weekend  

Hard work pays off: Made In Chelsea's Tiffany Watson showed off the results of her hard work in the gym as she posed in Calvin Klein underwear over the weekend  

Alongside the shot, Tiffany simply wrote: '#mycalvins'. 

Accessorising with just her silver belly-button piercing and and deep red cherry nail varnish, the blonde's hard work in the gym spoke for itself.

Tiffany had spent Saturday working out with her older sister Lucy, 25, - who quit Made In Chelsea earlier this year - and was evidently keen to show off her honed physique in all its glory.

Earlier in the day Tiffany posted a snap as she worked out alongside her sister, with the pair posing in the fitness studio with matching braided hair. 

Gym bunnies: The reality star, 22, spent Saturday working out with her older sister Lucy, 25, and was evidently keen to show off her honed physique

Gym bunnies: The reality star, 22, spent Saturday working out with her older sister Lucy, 25, and was evidently keen to show off her honed physique

Tiffany wrote:  'She had a braid I wanted one too'.

Tiffany made Sunday a day of rest, posting a sweet morning snap with her co-star boyfriend Sam Thompson.

Wearing a white hooded dressing gown alongside her beau, she wrote: 'Sunday's with my love @samthompsonuk' (sic).  

Stepping out later in the day, wearing black skinny jeans, a loose white jumper and camel jacket Tiffany made the most of time with friends and family.

Enjoying some time away from the gym, Tiffany wrote: 'Sundays are my favourite. Family roast and dog walk.'

Rise and shine: Whereas the start of the weekend was all about working out, Tiffany made Sunday a day of rest, posting a sweet morning snap with her boyfriend Sam Thompson

Rise and shine: Whereas the start of the weekend was all about working out, Tiffany made Sunday a day of rest, posting a sweet morning snap with her boyfriend Sam Thompson

Sam and Tiffany spent the summer in the South of France filming the Made In Chelsea spin-off alongside their co-stars.

But when they returned to UK shores, Tiffany complained that her man wasn't giving her enough attention or appreciating her enough.

In the Made In Chelsea series debut earlier this month, the blonde caught the eye of show newcomer Julius, only for her to realise it was Sam she wanted.

Tiffany's elder sister Lucy quit Made In Chelsea last month after four years on the E4 reality show. 

Puppy love: Tiffany told her Instagram followers she spent her Sunday enjoying a dog walk and then heading off for a roast with her family

Puppy love: Tiffany told her Instagram followers she spent her Sunday enjoying a dog walk and then heading off for a roast with her family

A spokesperson said: 'After four amazing years on Made in Chelsea, Lucy feels that now is the right time to explore some other exciting opportunities and projects that she is passionate about. 

'Being part of such a successful show has been an incredible experience for her, and she wishes everyone involved all the very best for the future.'

The announcement came shortly after Tiffany's friend Frankie Gaff revealed she was taking time away from the spotlight to concentrate on her relationship with her boyfriend James Dunmore, who she has been dating since 2015.

Frankie told BANG Showbiz: 'Lucy's not going to be in the next series. At the moment she's decided not to because she's loved up.' 

Dressed to impress: The blonde enjoyed a night out on Thursday when she attended the Faberge Say Yes To Colour launch party at Rook and Raven

Dressed to impress: The blonde enjoyed a night out on Thursday when she attended the Faberge Say Yes To Colour launch party at Rook and Raven

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