Lady Tatiana Mountbatten has revealed that she's so 'dedicated' to her fitness tracking watch that she seemingly wore it under her dress while attending a wedding.

The daughter of King Charles's cousin George Mountbatten, 4th Marquess of Milford Haven, showed how much she loved her gadget via Instagram Stories this weekend.

Snapping a photo of herself sitting in a car, the mother-of-one showed how she concealed the device - from prestige sports tech company WHOOP - under the sleeve of her flowy floral gown.

'Serious @whoop dedication,' she wrote. 'Anyone else do this?'

Elsewhere, she wrote 'wedding whoop', appearing to signal she was on her way to celebrate nuptials. 

Lady Tatiana Mountbatten has revealed that she's so 'dedicated' to her fitness tracking watch that she seemingly wore it under her dress while attending a wedding

Tatiana opted for a summery make-up look with a bronzed eye look and accesorised with golden earrings.

The 34-year-old pinned her wavy chestnut tresses back in a relaxed up-do for the outing.

A WHOOP membership - which is priced at a £229 upfront free for an annual subscription - comes with a watch and access to an app that features 'personalised insights, built-in coaching features, and weekly and monthly performance reports'.

The brand is beloved by stars like Cristiano Ronaldo, Michael Phelps, LeBron James and Tiger Woods. 

A 24-month membership costs £384 upfront. 

It is perhaps no wonder that sporty Tatiana - who often shares photos of herself horse riding on social  media - is a fan.

It comes as she earlier this year celebrated the christening of her baby daughter Elodie in a stunning church ceremony. 

Tatiana shared a carousel of images to her Instagram account in March. The new mother welcomed baby Elodie, now seven months, with her husband Alexander 'Alick' Dru last October. 

The daughter of King Charles 's cousin George Mountbatten, 4th Marquess of Milford Haven, showed how much she loved her gadget via Instagram Stories this weekend (right)

Tatiana looked flawless in a flowing ivory button-down gown, as she wrote: 'Some recent favourites.' 

The £3,450 made-to-order dress from Suzannah London was perfect for the occasion, and was embellished with elegant cuffs and a full skirt - and made from Italian silk. 

She paired the garment with a headband from John Boyd hats, which range from around £400 to £800 depending on the design. 

Her chestnut locks were perfectly styled, and she added dainty jewel-encrusted heels to complete the look.  

The equestrian cradled baby Elodie, her first child, who was wearing a traditional christening dress. 

In October, Tatiana revealed she had welcomed a baby girl, announcing the news via Instagram. 

Revealing her baby girl had been born in September, she wrote: 'One month of motherhood… and what a month it's been! Elodie arrived on 20th September. It's already going far too quickly.' 

Tatiana's followers were keen to send their well-wishes, including Flora Vesterberg, the late Queen Elizabeth II's cousin, who commented: 'Congratulations! She's adorable! Very proud of you xx. 

Alick Dru and Lady Tatiana Mountbatten pose during Royal Ascot 2021; the couple married in a stunning ceremony at Winchester Cathedral in 2022

The heartwarming post contained five photographs - the first showing baby Elodie asleep, wearing a knitted Babygro and matching bonnet, while grasping a toy rabbit.

The following image depicted Tatiana and Elodie lying on a bed, with the proud mother donning pyjamas as the newborn snoozed on her chest.

The third snap showed a close-up of baby Elodie holding on to her mother's finger, followed by displays of flowers and cards from friends. 

The equestrian announced her pregnancy in June, alongside a series of selfies that showed off her bump. 

Tatiana and Alick were married at Winchester Cathedral in July 2022. 

The bride stunned in a gown by British designer Suzanne Neville. Based on the existing 'Amelia' dress, it was adapted to include a bespoke three-metre train, incorporating embroidery from her mother's wedding gown.

Alick, an Eton-educated entrepreneur, popped the question during a skiing holiday in Verbier, Switzerland, just six months prior to the big day. 

He had taken the engagement ring on holiday with them and chose a romantic mountaintop spot to get down on one knee.

Tatiana is the second cousin once removed of King Charles, and the eldest child of George Mountbatten and his first wife Sarah Georgina Walker.

Her younger brother is Henry David Louis Mountbatten, Earl of Medina, while her stepbrother is Harry Wentworth-Stanley, the husband of Prince Harry's ex-girlfriend, Cressida Bonas. 

Although he does not herald from the same standing as his wife, Alick's family tree is still dotted with landed gentry.

The 31-year-old - whose full name is Alexander Bernard Molyneux Dru - is the son of Auberon Alexander Bernard Dru and Catherine Margaret Norden, who were married in Somerset in 1989.

Meanwhile Tatiana (pictured in 2021), who trained under Olympian Charlotte Dujardin, was educated at the elite £12,000-a-term Millfield private school in Street, Somerset

His father, known as Bernard, is the son of Major Alexander Dru and Gabriel Mary Hermione Herbert, and is a descendent of both John Vesey, 4th Viscount de Vesci, and Henry Howard Molyneux Herbert, 4th Earl of Carnarvon.

Alick was educated at Eton and studied History at Oxford, before founding Tripr, a social travel app, for 'travellers [who] would want to meet other travellers, as well as their friends.'

He then founded Spires Tutoring, before leaving the world of start-ups behind for a role on the M&A team at management consultancy Strategy&. This was followed by a two-year stint as an investor at SoftBank Investment Advisers.

Meanwhile Tatiana, who trained under Olympian Charlotte Dujardin, was educated at the elite £12,000-a-term Millfield private school in Street, Somerset.

Horse-mad Lady Tatiana once wanted to be a ski instructor, but now works training dressage horses.

Following stints in Denmark and Germany, 'Tatty' has settled in Windsor, where she runs a very smart equestrian yard.