Prince Harry is to launch the Walk of America expedition, the latest adventure by armed forces charity Walking With The Wounded.
Harry has become patron of the trek which will see a team of six veterans, from the US and UK, walk 1,000 miles from the west to the east coast in 14 weeks this summer.
Starting in Los Angeles - Meghan Markle's home city - on June 2 and finishing in New York on September 6, the team will walk by some of America's most famous cities and landmarks.
Expectations will be raised that Harry and his American bride-to-be will choose the US as the destination for their first joint official overseas tour.
Kensington Palace said: "The Walk of America will create a platform to tell the stories of wounded veterans and their individual journeys from injury to the present day, as well as encourage a wider conversation around veteran mental health.
"The expedition will also raise vital funds for veterans both sides of the Atlantic."
In 2013, Harry took part in a gruelling trek to the South Pole in aid of the Walking With The Wounded charity, joining a team of injured British servicemen and women in the race against groups from the US and the Commonwealth.
In 2015, he joined a group of wounded Afghanistan veterans for part of an epic 1,000-mile journey across Britain. Harry is not expected to take part in the Walk Of America.
During the launch at a central London hotel, the prince will meet the three British team members and make a speech.