The Duke of Sussex will carry out what is expected to be his final official royal duty, as Captain General of the Royal Marines, on Saturday.
Buckingham Palace confirmed Harry will be at The Mountbatten Festival of Music in London, in the honorary military role.
Harry spent 10 years in the forces and served on the frontline in Afghanistan.
He took over from his grandfather, the Duke of Edinburgh, as Captain General of the Royal Marines, in December 2017, after Philip spent 64 years in the role.
But as Harry steps away from royal life, his military appointments are being put on hold, and will not be used following Megxit, ahead of a review in 12 months.
A spokeswoman for Harry said: “The duke remains dedicated to supporting the military and mental health causes through his wider private work.”
He is retaining his ranks of Major, Lieutenant Commander and Squadron Leader.
The Duchess of Sussex is joining the duke at the Royal Albert Hall in London for the event, which will mark the 75th anniversary of the end of the Second World War and the 80th anniversary of the formation of Britain’s Commandos.
Musicians, composers and conductors of the Massed Bands of Her Majesty’s Royal Marines will perform.
Harry’s first official duty as Captain General after he succeeded his grandfather was to attend the music festival in 2018.