The pair went high tech at Buckingham Palace as they launched the Queen's new initiative.
The two brothers took part in a Google Hangout as part of the launch which aims to encourage young leaders across the Commonwealth to never "give up".
The Queen's Young Leaders Programme was launched with some help from entrepreuneur Jamal Edwards, who caught the royal duo for a picture.
Jamal hosted the hangout - the first live question and answer session to take place in the Palace - and the photograph's caption showed his disbelief.
"Had to get that Royal Pic w/ Prince William &Prince Harry loool. Today has been so surreal. I made history with hosting the 1st ever social hub in the palace. The Queens Young Leaders is an incredible movement that is going to change young peoples lives all around the world. It could be you!!! #SelfBelief #TheSearchIsOn", it read.
As well as young leaders from around the Commonwealth, other guests at the event included former Prime Minister John Major and Radio1 DJ Gemma Cairney, who helped Jamal with the hangout.
In the web chat with young adults from countries across the Commonwealth, William told those who had tuned in: "All I would say is believe in yourself – you've got a lot more to say then you think"
He added: "There are plenty people out there who have an open mind and will listen and care.
"They will listen to you and they want to help and those are the kind of guys and girls you need to target – so always believe in yourselves, don't give up."
The Queen's scheme was set up by the Diamond Jubilee Trust alongside Comic Relief and the Royal Commonwealth Society. It will honour 240 people aged 18 to 29 from all 53 Commonwealth countries. Those who are chosen will receive training, mentoring and help with networking.
They will also be sent on a one-week residential programme in the UK during which they will receive their award.