Owners Liz Logie and Véronique Lee decked out their store with British flags, food and fashion and blasted British invasion music such as the Beatles and the Rolling Stones in advance of Harry's arrival.
They even dressed the part, with Logie wearing a dress with the symbolic red poppies and Lee in a polo outfit and hat.
"Because we have several British designers in the store we thought we'd take the opportunity to highlight them and promote them in connection to Harry," Logie said. "It's just fun to have a theme and try and get people in the store. Everyone's an Anglophile for the day."
In addition to serving tea, cucumber finger sandwiches and Pimms Cup cocktails to customers, the store featured men's clothing from a British designer made out of recycled water bottles and fire hoses.
Although Harry is not expected to make an appearance in Greenwich outside of the polo grounds, Logie and Lee are holding out hope for a royal sighting on Greenwich Avenue - or in their store.
"I might be speechless for once in my life," Lee said with a laugh. "I was wondering - well, fantasizing, I guess - how would I address him?"
Logie wondered aloud about the protocol around the Prince as well. "I think he needs a curtsy."
Prince Harry will compete in the fourth Sentebale Royal Salute Polo Cup at the Greenwich Polo Club. Proceeds from the event go to Prince Harry's charity Sentebale, which raises money for children affected by AIDS/HIV and poverty in the African nation of Lesotho.
Greenwich Polo Club was co-founded by billionaire businessman and art collector Peter Brant. He is expected to participate in the charity match with the third in line to the throne.
The Greenwich event is invite-only and is closed to the public.
Click here to follow Daily Voice Greenwich and receive free news updates.