David Beckham was among the guests as t he Queen hosted a star-studded reception at Buckingham Palace to celebrate the first ever winners of her Young Leaders programme.
David Walliams, Sir John Major, Rob Brydon, Duncan Bannatyne and John Bishop also attended the ceremony which recognised the contribution of young people across the Commonwealth and saw 60 young people receive awards for their work in local communities.
Beckham told the audience: "I do not claim to be a public speaker and I am not an expert in the fields some of you are.
"I am honoured to be here this evening. With people like you I know the world will become a better place.
"Congratulations, well done and I'm very proud to be here.
"Good luck in the future. I'm sure you are going to make us all proud."
The awards were part of a five year programme established by The Queen Elizabeth Diamond Jubilee Trust in partnership with Comic Relief and the Royal Commonwealth Society to honour the Queen's Diamond Jubilee.
Edmund Page, 29, who is based in Cirencester, was chosen for his work educating refugees in Uganda and Kenya.
He said: "Picking leaders from all of the Commonwealth governments, that exemplifies inclusivity to all the countries involved.
"Tonight shows that you do not have to be anyone in particular to be a leader in your community.
"It would be great if more young people all over the Commonwealth applied."
Nicola Byrom, 28, from Oxford, was recognised for her work improving student mental health.
She said: "I had mental health difficulties myself as a teenager and struggled with an eating disorder. I found it quite hard when I moved to university as people did not talk about mental health much.
"I wanted to get more people talking about mental health.
"Everyone here is so inspirational. It's been great to be given the opportunity to meet them."
The ceremony was part of a week of events to help develop award-winners' leadership skills.
Earlier, the winners visited 10 Downing Street where they met David Cameron and asked him questions, before visiting Twitter UK headquarters and the BBC World Service.
Ms Byrom said Mr Cameron faced some "really quite difficult questions" from the young leaders.
She said: "They had a common theme in trying to get an answer to how to get governments engaged with grass-roots organisations."
Zoe Jackson, 25, from Hertfordshire, received the award for her charity work supporting young people who cannot afford access to performing arts.
Ms Jackson described meeting David Cameron as "incredibly inspirational".
The search for the Queen's Young leaders was launched in July 2014 by the Duke of Cambridge and Prince Harry and 60 winners will be chosen each year.
Sir John, chairman of the Queen's Diamond Jubilee Trust, thanked the princes for their support in his address: "Although they cannot be here this evening we are very grateful for the support and profile they have given to this programme on behalf of our majesty the Queen."
The Duke of York, Princess Beatrice, the Duke of Gloucester and Prince and Princess Michael of Kent also attended the reception, along with former BBC Radio 1 presenter Fearne Cotton, who is a supporter of the programme.
She said: "The ceremony was actually massively emotional and I wasn't expecting that at all. It was really special - live orchestra playing and everyone looking incredible and beautiful.
"There are special people out there that have that special leadership skill and this will give them the fire in the belly that they need to continue.
"I think this event is massively important. I do not think these people are necessarily getting a huge pat on their back every day for what they are doing."