She has never been a shrinking violet, but Mariah Carey is shrinking before our eyes as she revealed a slimline physique while out and about in London ahead of her O2 shows this week.

The pop superstar showed off a svelte frame as she enjoyed an off-duty evening with her adorable four-year-old twins, aka Moroccan and Monroe, taking them to Hamley’s toy store in London.

She glammed up her casual attire with her enormous 35-carat rock engagement ring given to her by billionaire James Packer, as she stepped out on Saturday.

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Fabulous darling! Mariah proved she is still on fire as she showed off new slimline figure while on an off-duty day in London at Hamleys on Saturday

Mariah looked foxier than ever in her all black get-up as she sauntered into the world famous toy shop with her children.

She squeezed her slender curves into skintight black leggings and added a rock chick edge with her biker jacket.

Her simple black top showed off a hint of her famous cleavage as she beamed upon arrival and she strutted her stuff with her honey locks styled sleek and straight with a chic centre parting.

Touch my body! Mariah oozed glam in her off-duty get-up as she revealed a svelte new figure on Saturday

New woman: Mariah looked incredible in her all black get-up which showed off her gym-honed figure to the max

Stunning: Mariah rocked a plush blow dry as she looked fresh-faced with her poker straight do

Her engagement ring from her billionaire fiance James Packer, which is estimated to cost a whopping $7.5million, was on full display on her perfectly manicured hands.

Their romance came to light in June last year, after her split from US actor, presenter and business mogul Nick Cannon.

Real Husbands of Hollywood star Nick is the father of Mariah’s gorgeous twins.

Since their split,  Mariah and James have been inseparable, enjoying a Mediterranean trip where they sailed around the Balearic Islands on James’ lavish yacht.

Twins set and match: Moroccan and Monroe looked delighted to get hugs from the Hamleys bear

Dem babies! Mariah made the most of her time off in London treating her tots to a visit to the toy store

‘Lamby’: Mariah captioned her shot ‘Lamby’ as she got to grips with an animal puppet

Although the exact date of the wedding is not yet known, Mariah is thought to be getting hitched mid-June.

Meanwhile Mariah has confirmed she will star in a new E! series about her life.

The 45-year-old singer officially announced the upcoming show, which will air on the same network as Keeping Up With The Kardashians

The superstar’s  eight-part ‘documentary series’ Mariah’s World will follow her life behind the scenes of her international tour.

The show began filming two weeks ago while Mariah was finishing up her Las Vegas stint.

Glittering: Mariah looked preened to perfection in her get-up