By Hilary Clarke, CNN

(CNN) -- The presence of Prince Harry's mother, Princess Diana, was subtly felt at her son's wedding to the American actress Meghan Markle, more than two decades after she was killed in a car crash in Paris.

Observers saw a clear nod to the mother-in-law Meghan will never meet in the train of her wedding dress, more transparent than the one worn by Diana when she married Prince Charles in 1981, but just as long.

The first lay address at the ceremony was made by Diana's sister, Lady Jane Fellowes who also gave a reading at Princess Diana's funeral in 1997. Lady Jane has rarely made public appearances since her sister's death.

Diana's younger brother, Earl Charles Spencer was also at the wedding with his wife Karen Villeneuve.

Her two older sisters, Lady Sarah McCorquodale and Lady Jane Fellowes, were also present, the latter has been chosen to give the reading at the ceremony.

Spencer's heartfelt eulogy at his sister's funeral, in which he pledged that her "blood family" would do all they could to steer her sons' upbringing "so that their souls are not simply immersed by duty and tradition," reportedly caused a rift with the royal family that has taken years to heal.

Many commentators see Meghan as the direct successor of Diana, dubbed "the People's Princess."

Singer Elton John, one of Diana's best friends, who released a new version of his 1974 hit "Candle in the Wind" dedicated to Diana after she died, was expected to perform at Saturday's wedding.

In a BBC interview last November marking his engagement to Meghan, Harry said his new bride and Diana would have been "best friends" and as "thick as thieves, without question."

Harry included two diamonds from his mother's own jewelry collection in Meghan's engagement ring, which he designed himself, "to make sure she's with us on this crazy journey together." The jewels flank a central diamond from Botswana, where the Prince Harry and Meghan's relationship blossomed.

St George's chapel, the wedding venue, was decorated by chosen florist, Philippa Craddock, with white garden roses, among other blooms. White roses were a favorite of Diana's and were included when one of the gardens at Kensington Palace -- where Harry and Meghan live in a cottage -- was transformed into a "White Garden" last year to mark the 20th anniversary of Diana's death.

Meghan has had to cut her past ties with organizations such as UN Women and World Vision as she takes on her royal role, but has made clear that she intends to continue her charitable work after the wedding.

On their first official joint royal appearance, less than a week after their engagement was announced, the couple visited a charity fair organized by HIV/AIDS charity the Terrence Higgins Trust, marking World AIDS Day. Diana was a champion of HIV/AIDS charities.