Queen Elizabeth Platinum Jubilee: Meghan Markle and Prince Harry's big weekend

Meghan, Duchess of Sussex and Prince Harry, Duke of Sussex at the National Service of Thanksgiving at St Paul's Cathedral in London on Friday. Photo / WireImage

They were back in the fold, sort of, but it's been a mixed Platinum Jubilee for the British royal family's sixth-in-line for the throne and his American wife.

Royals, royalists, passersby and viewers around the world have been swept up in a series of events marking Queen Elizabeth II's 70 years as monarch of Britain and 14 Commonwealth realms, including New Zealand.

Among those gathering for the occasion were the Queen's grandson Prince Harry and his wife of four years, Meghan Markle.

The Duke and Duchess of Sussex officially quit their royal duties 16 months ago and now live in California with Archie, 3, and baby Lilibet - named for her great-grandmother.

In an explosive tell-all interview with US TV host Oprah Winfrey before the baby's birth the couple levelled accusations including claims of racism within the royal family and that a suicidal Meghan had been denied mental health support.

There's also a long-running rift between Prince Harry and his brother, Prince William, while Prince Charles stopped taking his younger son's phone calls for a time.

However, 1-year-old Lilibet proved a unifying focus, meeting the Queen for the first time during a private visit to Windsor Castle, the Daily Mail reported.

Less uplifting was the reception the Sussexes received as they arrived and departed a service of thanksgiving for the Queen at St Paul's Cathedral, their first official engagement since quitting their senior roles in the royal family.

Initial cheers gave way to boos from the gathered crowd.

"Despite the fact they have stressed they have a huge amount of respect for the Queen, they are still in contact with her, the Queen has constantly stressed they are much-loved members of the family, the assembled crowd clearly had mixed feelings about them being here," Sky News commentator Rhiannon Mills said.

The couple also weren't on the Buckingham Palace balcony during Trooping of the Colour.

And eyebrows were raised when they were seated far from the Duke and Duchess of Cambridge at the thanksgiving service, but royal protocol that seating is done in order of seniority was the culprit, the Mirror reported.

Platinum Jubilee events continue today, with the Sussexes expected at the Derby at Epsom Downs early this morning New Zealand time and the Platinum Party at the Palace concert, under way from 7am NZT.