The Duke of Sussex will help mark a moment in history when he attends the first Major League Baseball (MLB) game played in Europe.
Harry will promote the Invictus Games Foundation when he watches the New York Yankees take on arch-rivals the Boston Red Sox at Queen Elizabeth Olympic Park on Saturday.
Former Invictus competitors from both the USA and UK will take part as the ceremonial first pitch is thrown on the ball park.
Earlier in June, the foundation announced it had become MLB’s charity partner for the weekend series in London.
“The support from these groundbreaking games will significantly enhance the Foundation’s ability to provide recovery opportunities for international wounded, injured, or sick serving or veteran armed forces personnel,” chief executive Dominic Reid said.
The foundation represents the Invictus Games, which Harry founded in 2014 as a multi-sport event for wounded or ill armed services personnel.
The royal’s baseball outing comes just over nine years since he threw the first pitch for hosts New York Mets against the Minnesota Twins on Britain’s Armed Forces Day.
The venue for this weekend’s series, a former Olympic stadium and now home to Premier League club West Ham, has undergone a dramatic transformation for the two matches between the Yankees and the Red Sox on June 29 and 30, with turf shipped from France and special dirt and clay shipped from Pennsylvania.
Interest in the games seems high, with organisers saying all 120,000 tickets sold out in 45 minutes and 70% were purchased within Britain.
The first regular MLB games to be played in Europe are expected to open up previously untapped markets for the organisation, which has already staged international events in Mexico, Japan, Australia and Puerto Rico.