The 35-year-old Prince will exchange vows with Ms Flohr this coming Saturday at the Metropolitan Cathedral of Athens. Unlike the first two ceremonies, which were both small and intimate, the third wedding is tipped to be much more extravagant.
Philippos’s well-connected family means there could be representatives from almost every monarchy in Europe.
The guest list is likely to include the Prince’s parents, Queen Anne-Marie of Denmark and King Constantine of Greece – who is also Prince William’s godfather – as well as other international royals.
Princess Eugenie and her husband Jack Brooksbank, who previously invited the couple to their own royal wedding in October 2018, are also likely to make the guest list.
As is Princess Beatrice’s husband, Edoardo Mapelli Mozzi, who is friends with Ms Flohr.
Prince Philippos’ family is closely linked to the British royal family. The Prince is named after his cousin, the Duke of Edinburgh.
Prince Philippos was born in London in 1986, at St Mary’s hospital, and raised in a 13-bedroom house bordering Hampstead Heath with four older siblings, Princess Alexia, Crown Prince Pavlos, Prince Nikolaos and Princess Theodora.
Princess Diana, his godmother, was a frequent visitor, along with Prince William and Prince Harry.
His other godparents include the late Prince Philip and King Juan Carlos of Spain.
LIVE UPDATES: Royal Family LIVE: Out of control! Meghan’s political plea sparks fury
Other Brits expected to attend the nuptials include Vogue writer Alice Naylor-Leyland and her husband Tom, who hosted the couple’s second wedding at their home in Cambridge.
Alice was named as one of Tatler’s “society swans” in 2018, and Tom is the son of Baronet Sir Philip Naylor-Leyland, part of a land-owning dynasty that controls the 17th Century Talbot hotel in Malton, North Yorkshire.
Prince Phillipos and Ms Flohr held their first wedding last December in a small civil ceremony in St Moritz, Switzerland.
The only witnesses were Prince Phillippos and Ms Flohr’s respective fathers.
The intimate ceremony was then followed by a high society springtime celebration in Cambridgeshire.