Prince Harry on Thursday made his first public appearance since his shock return to Britain from the United States with his family three weeks ago.

Harry, who quit Britain for California six years ago with his wife Meghan amid tensions with his family, attended a fundraising evening for his Invictus Games for wounded veterans in London. 

Dressed in a smoking jacket adorned with his military decorations, the 42-year-old prince took selfies with injured former soldiers at the event. Meghan did not accompany him.

Along with their two children, Harry and Meghan landed back in the UK on August 26 and have kept a relatively low profile since. 

Speculation abounds over the reasons for their return, given that the Duke and Duchess of Sussex left in the middle of a falling-out with his family, which only worsened after Harry published his tell-all memoir "Spare".

His appearance at the event comes after the brother of Princess Diana, Harry's mother, unleashed a barrage of stinging criticism against King Charles III's behaviour towards his ex-wife.

In a memoir being serialised in the Daily Mail newspaper, Charles Spencer claimed that the then-prince Charles sounded "giddily elated" the night Diana died in a car crash in 1996.

The claims have prompted Buckingham Palace to issue an unusual rebuttal, insisting that Charles "is mindful that the pain of fraternal grief can cloud reason, affect judgement and colour memory".