And they sealed those places with a kiss and raucous support.
Chelsy Davy, 21, who has been dating Harry for about three years, planted a smooch on her prince, while Kate Middleton smiled supportively at Prince William from just two rows behind her concert-promoter boyfriend at Wembley Stadium.
Middleton and William, both 25, have recently been seeing each other again after breaking off their five-year relationship in April, friends have told PEOPLE.
Dressed in a white trench coat and a black-and-white print dress by Issa, Middleton rocked out to the show among the other young royals and friends, putting her arm in the air to "Shine" by former boy band Take That and grooving to Lily Allen and Nelly Furtado.
The charitable concert – held on what would've been Diana's 46th birthday, 10 years after her death – was opened by the princes, with a rousing "Hello Wembley!"
"This evening is about all that our mother loved in life – her music, her dance, her charities and her family and friends," William told the 60,000-strong crowd, after being introduced by Elton John.
Army officer Harry, 22, mindful of those he would have been serving alongside in Iraq had he been able to go, added a word of praise, "I wish I was there with you. I'm sorry I can't be. To you and everyone on operations we'd both like to say stay safe."
Harry told the crowd that there was some pressure on the princes to come up with something funny to say – but, to laughter, he added, "We will leave that to the funny people, and Ricky Gervais [who is presenting later]."
William ended by introducing "one of our mother's favorite bands," Duran Duran. The band played three songs, including their hit "Rio" – a special request from the princes. Singer Simon Le Bon dedicated their song "Wild Boys" to William and Harry.
Matt Dunham / AP
The show included acts from Diana's era (Rod Stewart, Supertramp and Bryan Ferry) and those from her sons' (Diddy, Kanye West and Fergie). Also thrown in: a star turn from The Office's Ricky Gervais.
Fergie praised Diana's sons for doing such a great job. "What better people to do it?" she told PEOPLE. "They threw her an amazing party for her. She would be so proud of them."
Natasha Bedingfield, who sang "Unwritten," tells PEOPLE, "When someone dies and the anniversary comes around you can sit around being sad, but it's great that they have taken the positive route and said, 'Let's carry on the legacy.'
"It's in their blood."
After a display of perfect pop from Elton John, who sang "Tiny Dancer" and "Are You Ready for Love," the princes ended the evening with a thanks and a retrospective of home movies from Diana's childhood. Looking forward to days when he and Harry could carry on the work of both his mother and father, William said, "For us, this has been the most perfect way to remember and this is how she would want to be remembered."