The Duke of Sussex appeared to be mistaken for his older brother on Friday during a charity event in California.

Harry attended the annual One805Live! charity concert on his own after Meghan pulled out at the last minute due to illness.

Stars such as Cameron Diaz, Zoe Saldana, Jeff Bridges and Pink attended the event to celebrate the heroism of Santa Barbara’s first responders while Richard Marx was one of the musicians to perform.

After the charity event, the singer was seen chatting with the Duke of Sussex backstage.

But Marx’s wife, Daisy Fuentes, mistakenly tagged Prince William’s Instagram account and Princess Kate Middleton’s Instagram account after uploading a photo of her husband with Harry at the event.

Fuentes corrected the error, but ended up tagging a fan-run Prince Harry account instead.

Earlier, Marx had appeared not to recognise the Duke of Sussex as he waited for him by the side of the stage.

Marx went to walk past the Duke but was then pointed in Harry’s direction following his performance at the concert.

Notifying the performer, they swiftly prompted “Richard, Prince Harry” as they gestured to the duke.

Before the clip cuts out, the royal is heard saying: “Hey! Well done.”

Harry also took to the stage at the fundraising event, which was hosted by Kevin Costner, to honour Santa Barbara County air support pilot Loren Courtney with an award celebrating his work.

“As you’ve probably heard already, 22 years [of] military service over 10,000 hours and rarely sees his family because he’s always here flying helicopters,” Harry said.

Meanwhile, Courtney told the crowd he continues to serve his community because “I love doing it and I love doing it for the county of Santa Barbara.”

It comes after Prince Harry revealed what “gives him hope” as he honoured Princess Diana on his New York trip without Meghan Markle.

The Duke of Sussex spoke on stage today to discuss mental health with two young winners of a legacy award in his mother’s memory.

His attendance was part of the 14th Concordia Annual Summit, in support of The Diana Award.

Harry addressed The Legacy Award winners, Chiara Riyanti Hutapea Zhang from Indonesia, and Christina Williams from Jamaica.

At the start of the Q&A session, the Duke of Sussex was asked by Diana Award chief executive Tessy Ojo “what are you hopeful for?” to which he joked “can I go last?”

“The reason why I wanted to go last is because these guys are the ones that give me hope,” he said after speaking to Chiara and Christina.

The news comes after Harry kicked off his New York with a glitzy dinner over the weekend.

He was pictured during a high-level dinner organised by the World Health Organization (WHO) in the Big Apple on Sunday.

The event was to honour survivors of childhood violence and discuss its impact on mental health.

He rubbed shoulders with Queen Mathilde of Belgium and the Belgian prime minister Alexander De Croo.

Officials from other countries included Sweden, Colombia, Zimbabwe, Georgia, Canada, Iceland and Brazil.

Actor Forest Whitaker was also in attendance, but Harry’s wife Meghan was noticeably absent.

The usually inseparable pair have spent time apart since Harry’s lads’ trip to celebrate his 40th birthday this month.

Harry turned up alone at a charity event in California at the weekend after Meghan pulled out at the last minute having fallen ill.