Prince William arrives for usher duties at Duke of Westminster's society wedding of the year to Olivia Henson as royal is cheered by delighted thousands-strong crowd

Prince William has arrived at the Duke of Westminster's society wedding of the year to Olivia Henson.

The Prince was cheered on by onlookers as he appeared near Chester Cathedral for the nuptials of his old friend Hugh Grosvenor. 

The 7th Duke, 33, universally known as 'Hughie' to aristocratic friends, is estimated to be worth £10.42billion, making him the richest man under 40 in Britain. 

He is the godfather to Prince William's son Prince George and Prince Harry's son Archie. William will be an usher at the service among 400 or so expected guests - while Harry will not be in attendance. 

Hugh will wed Olivia, 31, at the cathedral in Cheshire at midday, with guests jetting in from around the world. 

Princess Eugenie will also be among the many guests at the event in the 11th Century Cathedral. But the Princess of Wales, who has been out the spotlight as she undergoes preventative chemotherapy, is not expected to attend. 

Miss Henson will arrive at the Cathedral just before noon in a vintage 1930 8-litre Bentley owned by the Grosvenor estate. 

After the ceremony finishes around 1pm guests will enjoy a lavish reception with a lemon wedding cake at the Grosvenor family seat, Eaton Hall, just outside Chester. 

The Duke will pay for free ice cream, gelato and sorbet for Cheshire locals from three local independent cafes so they can join in the celebration. 

Photos from this morning show excited royal fans forming a crowd outside the cathedral ahead of the Church of England ceremony starting at midday. 

The fans have been gathering since 6am this morning, hours before the ceremony is due to start. 

Maths tutor Catherina Rhodes, 59, of Chester, said: 'It's an exciting day. I have always loved the royal family especially the Queen.

'I was taken down to Buckingham Palace when I was aged six.

'My uncle worked at the stables and helped teach the Queen to ride. Since then I was entranced by the royal family.' 

She added: 'It's great for the city.'

Pharmaceutical trainer Helen Jackson, 55, said: 'I went for a drink in the Grosvenor hotel last night and saw Princess Eugenie having a drink.

'So I know she's going to be here today.

'It's fabulous for [...] Chester.

'I came to see the royals when the Queen and Megan Markle came here just before.'

Pensioner Ann Beck arrived at 8am. She said: 'I wanted to come to support the family as they are from Chester and of course the royals.'

A staggering 100,000 flowers have been planted throughout the city - all paid for by the Duke - which will be donated to charity following the ceremony. 

This week a floral arch was constructed around the huge West Door of the 1,000-year-old Cathedral in the heart of the city. 

On a road into the city near the entrance to the Grosvenor Hospital, staff dressed a pair of mannequins in suit and wedding dress with photos of Hugh and Olivia's faces attached. 

Given the presence of the heir to the throne at the event, security precautions have also been in evidence, with detectives seen chatting with local Cheshire Police officers outside the Cathedral this week. 

Police sniffer dogs were seen checking drains around the precincts of the building for any traces of explosives.

Eaton Hall, a mock French chateau set in 10,872 acres of Cheshire (50 acres of which is elaborate formal gardens) is where the couple intend to live after they are married, and is the perfect place for a party. 

Cheshire Farm Ice Cream, based in the heart of Chester Market, will be offering a range of Cheshire Farm single-scoop ice-creams or slices of a new lemon-sponge flavoured arctic roll.

The lemon-flavoured arctic roll has been specially created in acknowledgement of The Duke and Olivia's lemon-flavoured wedding cake that guests will be served at the wedding reception.

Ed Warrington, owner of Cheshire Farm Ice Cream outlets, said: 'As a local business we're delighted to be part of The Duke and Olivia's initiative to provide free ice cream to the public in celebration of their wedding.

'All at Cheshire Farm Ice Cream wish them the very best for their wedding day.'

The couple have been scrupulous about not giving away details of the reception and 'we have also been asked not to do any social media posting when we get there', said a guest.

It is likely to be a green event as both Hugh and Olivia are eco minded, and it is understood that flowers used at the ceremony and reception will be pressed and made into sustainable artworks afterwards, rather than simply being thrown away.

Olivia, who went to Marlborough College, like the Princess of Wales and Princess Eugenie, is senior account manager at Belazu, an environmentally friendly company which imports chef-quality, sustainably-sourced ingredients.

Hugh has increasingly started to initiate various eco-friendly practices, including renewable energy projects, green building codes and biodiversity conservation efforts.