The Windsor home will remain the Duke and Duchess of Sussex's U.K. residence, but they will share it with the couple when they return.
Harry, 36, and Meghan, 39, who are currently residing in their Santa Barbara, California, home, have offered up their Windsor, England, estate to the 30-year-old daughter of Prince Andrew and Sarah "Fergie" Ferguson.
The location remains the Duke and Duchess of Sussex's U.K. residence, but ET has learned that the Sussexes are delighted to be able to open up their home to Princess Eugenie and Jack Brooksbank as they start their own family.
ET has learned that the Sussexes will retain financial responsibility for the property. The couple announced back in September that they had paid off the $3.1 million they spent on renovations to Frogmore Cottage. They have not moved out and plan to share the property with Eugenie and Jack when they travel to the UK.
Frogmore Cottage was renovated by Harry and Meghan to be a five-bedroom home, offering up plenty of space for both families if they have to share in the future.
But with the coronavirus pandemic continuing on, Harry and Meghan have no concrete plans to return to the U.K. and haven't seen Frogmore Cottage since they last visited in March.
As was previously reported, Harry and Meghan have no intention to returning to the U.K. for the holidays this year due to the global pandemic.
ET previously learned from a source close to Harry and Meghan that it is "fully anticipated that [the couple] will be at home in California and not be in the U.K. for Christmas." A source told ET that members of the royal family are "disappointed" that they won't be seeing 1-year-old Archie this holiday season.
Once COVID restrictions relax, Harry and Meghan could potentially make a return to Europe for the rescheduling of the Invictus Games, Trooping the Colour, or Prince Philip's 100th birthday, which will fall at the same time in June 2021. No definitive plans have been made amid the pandemic, but these are all dates being kept in mind.
Eugenie, meanwhile, is preparing for the birth of her first child, whom she is expecting in early 2021.