We all know that Cressida Bonas and fiancé Harry Wentworth-Stanley announced their engagement on Instagram on August 19. The British model and actress' fiancé popped the question to her on a holiday in Nantucket, Massachusetts.

But, what we don't know is that Cressida Bonas' engagement ring links her to the British Royal Family yet again. The 30-year-old was the last girlfriend Prince Harry had before he wed Meghan Markle. In fact, she is also close friends with Princess Eugenie.

According to Express, the actress's unique, octagonal, retro-inspired engagement ring has been designed by British fine jewellery designer Bear Brooksbank. The designer is a cousin of Jack Brooksbank, Princess Eugenie's husband.

Bonas' engagement ring is unique and a clear shift from the traditional diamond solitaires. It is distinctive and set in yellow gold. It features a brilliant-cut diamond in the target style and 'halos' of rubies and diamonds in an octagon shape.

"The target ring is a very beautiful, classic, tried and tested design which is a crowd pleaser, but it's also interesting. For men doing it on their own, it's an unusual but safe choice: so you're not just freestyling," said Brooksbank.

cressida bonas
Cressida Bonas attends the London Evening Standard Theatre Awards at the Theatre Royal on December 3, 2017 in London, England Getty

Bonas is known for previously dating Prince Harry from 2012 to 2014. And, the connection doesn't end there! Her fiancé Harry Wentworth-Stanley's stepfather, George Mountbatten is Queen Elizabeth's cousin. Mountbatten is the 4th Marquess of Milford Haven. He is a descendent of Princess Alice, the second daughter of Queen Victoria.

Wentworth-Stanley works as an associate property surveyor for real estate firm, Savills. He met Prince William as part of the Row for James team in June 2018. The four rowers crossed the Atlantic Ocean to raise funds for James' Place. It is a non-clinical centre for men in suicidal crisis started by Wentworth-Stanley's parents, Clare Milford Haven and Nick Wentworth-Stanley. They started the centre after their son, James, committed suicide at the age of 21, in 2006.

Wentworth-Stanley's mother, a former journalist, also has royal connections. She was a friend of Princess Diana and Sarah Ferguson.

Prince Harry