Pippa Middleton looks gorgeous in blue at Lady Gabriella Windsor's Royal Wedding

A royally impressive collection of British aristocracy have come out in force for the Meghan Markle's missing as Prince Harry attends Lady Gabriella Windsor's wedding - who is a cousin of Her Majesty Queen Elizabeth II.

While HM The Queen will of course be the biggest star to attend the nuptials of Lady Gabriella and Thomas Kingston at St George’s Chapel in Windsor today, a treasure trove of other familiar faces have already descended on the church to watch the happy day unfold.

Pippa Middleton and her husband James Matthews (the brother of Made In Chelsea star Spencer Matthews) have made their way to the chapel.

Pippa was seen wearing a delicate summer dress in a charming blue shade, while James opted for classic penguin suit.

James Matthews and Pippa Middleton attended the wedding together (Tim Rooke/REX)

A beaming Prince Harry was also among guests - arriving with Sophie Winkleman with no sign of his wife Meghan Markle (Stephen Lock / i-Images)

Meghan Markle's missing as Prince Harry attends Lady Gabriella Windsor's wedding  

The couple were joined by Pippa’s parents, Michael and Carole Middleton - while Pippa’s sister, Catherine, Duchess of Cambridge and her husband Prince William, Duke of Cambridge, are not expected to arrive.

Adding to the Middleton contingent, however, was Pippa and Kate’s brother, James, who attended alongside his girlfriend, Alizee Thevenet.

Stars of the small screens are among guest - with Downton Abbey creator Julian Fellowes spied gingerly walking towards the ceremony while flanked by an army of women.

Duke and Duchess of York arrive at wedding of Lady Gabriella Windsor

Michael and Carole Middleton, James and Pippa, and James Middleton and Alizee Thevenet were all there (REUTERS)

Sarah Ferguson, the Duchess of York, arrived wearing soft pink and ruffles (Tim Rooke/REX)

Princess Michael of Kent was in attendance with her son Lord Frederick Windsor - who is married to Peep Show actress Sophie Winkleman (REUTERS)

Meghan Markle 'will be hands-on mum and make her own baby food' says best pal  

While Peep Show star Sophie Winkleman (sister of Strictly Come Dancing host Claudia Winkleman) was also due to attend alongside her husband Lord Frederick Windsor.

Prince Harry, Duke of Sussex, was a surprise guest on the day - having been believed to not be attending.

The Prince recently became a first time father as his wife, Meghan, Duchess of Sussex and official Princess of the United Kingdom, gave birth to a son named Archie on May 6.

Downton Abbey star Julian Fellowes was there (Tim Rooke/REX)

Michael and Carole Middleton looked excited to be there (Tim Rooke/REX)

Dashing groom Thomas, right, looked slightly nervous as he turned up at St George's Chapel (Getty Images)

Prince William says losing mum Princess Diana was a 'pain like no other'  

Harry attended without his wife and child - but with a beaming smile that suggested he is still on cloud nine after becoming a father.

The big day marks the third Royal Wedding in a year - following the marriage of Prince Harry to Meghan Markle last May, and the nuptials of Princess Eugenie to Jack Brooksbank last October.