Happy: The Duchess of Cambridge is given flowers (left) and walks with Chief Scout Bear Grylls (right)

Kate has worn her Whiteley Cappuccino hat on several previous occasions, including the Epsom Derby.

The event is a day of celebration, bringing together 400 Queen’s Scouts and their invited guests to celebrate the achievements of young people and young adults who have achieved the prestigious award.

It is gained by carrying out regular community service for a year, learning new skills, completing a four day expedition in unknown terrain; taking part in a residential project and then sharing what has been learned with their peers.

During the event, The Duchess of Cambridge spent time talking with some of the 400-plus Queen’s Scouts from around the UK and the Commonwealth.

The Duchess also met gallantry award holders, who have been nominated for their bravery and heroism and meeting adversity in their everyday lives.

The Duchess also met gallantry award holders, who have been nominated for their bravery and heroism

The Duchess of Cambridge look was finished off with a fawn pill box hat, previously wore at the Epsom Derby

Chief Scout Bear Grylls (centre) was also at the ceremony at Windsor Castle

The ceremony celebrates the achievements of 400 young people who were given with the award

The tradition of the annual celebration event within Windsor Castle dates back eighty years.

Since its inception, tens of thousands of young men and women have been honoured with a King’s or Queen’s Scout Award for their own outstanding personal achievements.

Today, The Scout Association hailed the Duchess, who volunteers occasionally with a Cub Scout group close to her home in North Wales, for a sharp increase in the number of adult volunteers.

A spokesman for the Scouts said the Duchess had done around half a dozen volunteering sessions with her local cubs this year.

‘She loves it. I can’t see her giving it up,’ said Simon Carter, assistant director of the Scout Association.

The Duchess is one of 2,812 new adult volunteers to join this year. These figures represent the second biggest increase in adult volunteers since 1986.

The tradition of the annual celebration event within Windsor Castle dates back eighty years

Catherine met hundreds of Scouts from across the UK and Commonwealth at the ceremony

The Scouting Association credited Kate with boosting volunteer numbers within the organisation

As well as attracting more adults the total number of teenagers in Scouting has almost doubled in the last 10 years, from 23,446 in 2003 to 40,578 in 2013.

However, despite attracting more adults, the Movement still has 37,867 young people on waiting lists who are unable join up because even more adult volunteers are needed.

Bear Grylls, Chief Scout, said: ‘It’s great that so many adults are joining the Scouts, and I am sure the increase has had much to do with the Duchess of Cambridge becoming a Scout volunteer last year.

‘The Duchess is an incredible role model and she helps us show that Scouting’s not just for boys.

‘She’s also such a generous volunteer and everyone is so excited to have her in the Scouting family. Many people have followed her lead and are getting involved and enjoying the adventure.’

It is the first time Kate has stepped in for the Queen, pictured with Bear Grylls during last year’s event

Bear Grylls said the Duchess is an ‘incredible role model’ and proves Scouting is ‘not just for boys’

Chief Scout Bear Grylls said the Duchess is a ‘generous volunteer’ within the ‘Scouting family’

He added: ‘All the young people at Windsor Castle ceremony have given so much time and energy to achieve their Queen’s Scout Awards, and I admire their spirit so much.

‘They are huge inspirations to all the other Scouts across in the UK and I am so pleased that both the Duchess of Cambridge and Scouting have honoured them. Reaching Queen’s Scout is a remarkable achievement and along the way they will have all had the adventure of a lifetime.’

As one of the UK’s most high profile figures, it’s hoped the Duchess’ involvement will inspire other adults to get involved in Scouting.

With waiting lists at an all-time high of almost 38,000, there is an urgent need for more volunteers, in order to meet the growing demand.

The Duchess, pictured during a visit to the Great Tower Scout Camp last month, has volunteered with her local North Wales cubs about six times this year

The Duchess of Cambridge was last seen in public with the Queen when she accompanied her on a visit to Baker Street underground station to mark the 150th anniversary of the London Underground where she was given a ‘Baby on Board’ badge

Sazeda Patel, a volunteer from Blackburn, said: ‘I didn’t think I’d have the time to volunteer, but the Scouts make it really easy to volunteer around my other commitments – and they let me give as much or as little time as I’m able.

‘I did my training with the Duchess in Cumbria last month and had a great day with her. If someone as busy as the Duchess can find time to volunteer, anyone can! I couldn’t recommend volunteering more highly; I just wish I’d got involved sooner.’

All this underlines the fact that Scouting is the largest co-educational youth Movement in the UK. On the back of eight consecutive years of growth, total membership has increased over 20% since 2005, to 536,787 this year.

The Queen attended the event last year and in 2007.