The 35-year-old actress partied with some of the prince's closest friends at the nuptials of Tom 'Skippy' Inskip and literary agent Lara Hughes-Young in Montego Bay on Thursday (02Mar17), People.com reports.
Inskip and Harry are childhood friends after meeting at prestigious private school Eton College.
For the luxury wedding in the Caribbean, Meghan wore a long floral bird print maxi dress by designer Erdem, while Harry, who was one of the groom's 14 ushers, wore a navy blue blazer suit with a white shirt.
In a picture obtained by People.com from the nuptials, the loved-up couple was seen chatting to a friend on a beachside table, with Meghan resting her hand lovingly on Harry's back.
It is thought the Jamaican ceremony is the first time the Suits actress has accompanied Harry to a wedding, after meeting most of her boyfriend's closest friends in London over the last few months.
The pair arrived in Montego Bay on Wednesday (01Mar17), with Meghan apparently flying into the country separately from her home in Toronto, Canada.
Harry is also planning on staying in the Caribbean for at least a week at the Round Hill Hotel and Resort in Montego Bay, a private resort of luxury villas and oceanfront rooms, where most of the wedding party are also staying.