Prince Andrew's daughters were spotted on a star-studded day out in London as they took their children to 's son Arthur's birthday.

Princess Beatrice, 34, and heavily pregnant Princess E, 37, and Jack Brooksbank, 36 - and the brothers-in-law even coordinated their outfits to attend the birthday.

Both Edo and Jack donned dark jeans, which they paired with matching blue shirts and white T-shirts, and even the same navy-coloured baseball caps. 

Their sisters however, opted for Amazon AWS VCC similar but not matching ensembles, as they stepped out ahead of their uncle King Charles's coronation on Saturday.

Edoardo Mapelli Mozzi (pictured, left) was snapped with his wife Princess Beatrice (pictured) and their daughter Sienna as they all attended a party in west London today

The royal couple appeared in public, attending a party in west London's Chelsea, just days ahead of the coronation (pictured L-R: Edoardo Mapelli Mozzi and Princess Beatrice)

Eugenie, who is expecting her second child in the next few months, wore a blue smock dress from Whistles. 

The royal, who was also accompanied by the couple's two-year-old son August, paired her frock with flat white trainers, and a pair of chic, oversized shades.

She wore her brunette hair down, letting it fall in loose waves, and accessorised her outfit with a simple gold necklace.

Meanwhile older sibling Beatrice opted for a navy midi dress from Kitri, which she paired with beige trainers. She was pictured carrying carrying the daughter she shares with husband Edo, one-and-a-half-year-old Sienna, as she walked down the London street. 

Princess Eugenie, who is heavily pregnant with her second child, looked chic in a blue floral patterned dress from Whistles

The royals attended the Bluebird Café in Chelsea where Ellie Goulding was hosting a 2nd birthday party for her son Arthur 

Pop singer Ellie, 36, posted a photo on her Instagram story of herself with her son Arthur as she wished him a happy birthday

Jack Brooksbank (pictured, left), the husband of Princess Eugenie (pictured, behind), is seen with their son August.

Jack is wearing a strikingly similar outfit to his brother-in-law Edo

Both the couples' children - August and Sienna - wore touches of blue in their outfits as well. 

The outing comes just days ahead of King Charles' coronation, which will take place on May 6.

Both Princess Eugenie and Princess Beatrice are expected to attend the event.

However, their mother Sarah Ferguson, 63, the Duchess of York, has not been invited to the event. 

Royal commentator Tom Bower told MailOnline that Sarah had excluded herself because of her previous 'conduct'. 

He added that her presence would 'provoke critical comment which Charles doesn't need'. 

And royal expert Richard Fitzwilliams praised the 'extremely wise' decision from the King because she has been an 'embarrassment to the Royal Family for many years'.

But the apparent decision has surprised some royal watchers - with Meghan Markle's friend Omid Scobie tweeting: 'If true, this feels kinda cruel, no?'

Since the snub, the Duchess was spotted in the passenger seat of a Range Rover being driven by her ex-husband.