LONDON -- Major league baseball's first game in Europe received a royal launch.

Prince Harry and wife Meghan, the Duchess of Sussex, took part in the ceremonial first pitch before the New York Yankees played the Boston Red Sox. The couple left month-old son Archie home as Meghan made one of her few public appearances since giving birth.

They strolled to the mound at London Stadium along with 10 participants in the Invictus Games, an international project started by Harry to give wounded military men and women a chance to compete.

Harry did not address the crowd -- or risk throwing the first pitch and having it land in the dirt. He instead ceded honours to Invictus veterans, who performed credibly.

Meghan wore a simple black dress and skipped the spiky heels she sometimes favours for her walk on the infield dirt (brought from the U.S.) and artificial turf (from France.) Harry wore black slacks and a matching shirt.

They chatted with pitchers CC Sabathia of the Yankees and Chris Sale of the Red Sox during the ceremony.

Harry has played polo in public many times and flown a helicopter with British forces in Afghanistan. He has also hiked in the Arctic with wounded veterans. But Saturday marked his first public appearance at a major league baseball game.

The couple plan to resume a full-scale royal schedule in about four months with a trip to South Africa that will mark Archie's debut on the international stage. Harry will continue on his own to other African countries. The date and itinerary have not been set.

Harry and brother Prince William have taken increasingly visible public roles in recent years as their grandmother, 93-year-old Queen Elizabeth II, eases her schedule and refrains from long flights.