The celebration — which till take place Tuesday, October 19, at Kensington Palace — is a private reception for the donors who funded the statue of Harry and Prince William's mom that was unveiled over the summer on what would've been the princess' 60th birthday.
The Duke of Cambridge will be in attendance, according to PEOPLE, while the Duke of Sussex is privately reaching out to the donors.
Meanwhile, Harry and Meghan have been very busy in the U.S. ever since they moved to California last year to start their lives over. OK! reported the royal-turned-Hollywood couple recently took a trip to New York City for the Global Citizen Live concert, and the red-headed prince is set to return to the Big Apple in November for the Intrepid Museum’s Salute to Freedom gala.
Despite Harry missing the upcoming event honoring his mom, he returned across the pond to attend Diana's July 1 statue unveiling, which marked his second time back in London since his and Meghan's royal exit, dubbed Megxit.
Harry was reportedly greeted with icy welcomes from the royals when he first reunited with his family in April for grandfather Prince Philip's funeral. Meghan — who gave birth to daughter Lilibet Diana in June and also shares 2-year-old Archie with her hubby — did not attend either royal occasion.
The 37-year-old had a brief clear-the-air talk with his brother and dad, Prince Charles, upon his first return, but the family has a long way to go if they want to reconcile their estranged relationships.
However, it seemed like Harry and William took a step in the right direction at their mom's statue unveiling in the Sunken Garden, as they were seen smiling alongside each other and greeting fellow royal members together.
Harry and William — who lost their mom at 12 and 15, respectively, after her Paris car crash in 1997 — released a joint statement at the time, per the palace, that read: "Today, on what would have been our mother’s 60th birthday, we remember her love, strength and character – qualities that made her a force for good around the world, changing countless lives for the better."
Harry has reportedly been at odds with his family ever since the royal member and Suits alum opened up about their lives behind palace walls last March, with Harry accusing his dad and brother of being "trapped" in royal life.