The Duke of Sussex is guest of honour at the event in Guildhall in the City of London where he is expected to deliver an impassioned speech in front of an audience which includes former competitors and representatives of the military. Harry founded the international sports tournament in 2014 for servicemen and women who had been injured in the line of duty.
Since then he has overseen the Games in Orlando in 2016, Toronto in 2017 and Sydney in 2018.
Harry, 34, chose the 2017 event as the first official outing with his then-girlfriend Meghan who was at the time living in the Canadian city.
Last year, five months after he and the former actress wed in Windsor, the couple made the trip Down Under where they attended the opening ceremony of the 2018 Games.
Prince Harry delivered a speech in front of former Invictus Games competitors (Image: REUTRS/GETTY)
The Duke left Meghan and baby Archie at home as he stepped out for the event in London (Image: PA)
The Duke was inspired to launch the games after attending the Warrior Games in Colorado in 2013, a sporting competition for wounded, sick or injured military personnel run by the Department of Defence.
In a speech in 2017 Harry spoke about being moved by what he saw - men and women defying the odds through sports.
He said: “Sport is what would make the difference.
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The new dad chatted to past competitors before giving a speech at the reception (Image: PA)
“Sport would help these guys and girls fix their lives and reconnect with those around them. And the