Prince Charles and Joe Allbritton: Still friends? (Ben Stansall/Getty Images; Rebecca D'Angelo for The Washington Post )

Look s like the friendship of Prince Charles and Joe Allbritton has hit a bump over a business deal gone sour.

The multimillionaire businessman is a close friend of the future king of England and a big donor to his D.C.-based Prince of Wales Foundation (he’s given more than $3 million) and other charities. The two are so close that Allbritton and his wife were the only Washingtonians invited to April’s royal wedding, and Allbritton loaned his personal jet for the prince’s trip here in May.

Now it turns out they were business partners, too.

After 14 years, Robert Higdon just resigned as head of D.C.-based Prince of Wales Foundation. (Olivier Douliery/The Washington Post)

According to London’s Sunday Times, Allbritton promised to invest $3.25 million in Duchy Originals, the prince’s line of expensive organic cookies and treats. The business was failing when Allbritton stepped in two years ago and gave a first payment of $750,000 to help it expand into the U.S.

In August 2009, the prince partnered with British supermarket Waitrose to distribute his line — and last week, Waitrose officials told the Times that Allbritton would not be part of the U.S. push. It’s unclear when store officials became aware of Allbritton’s investment; the paper reported that the former Riggs Bank magnate and his associates got the bad news this summer during a “tense encounter” with a palace official.

A spokesman for Clarence House disputed that account, telling us Tuesday that Allbritton was “informed of Duchy Originals’ pending deal with Waitrose, including worldwide rights, before it was even signed in August 2009. The worldwide rights were always a part of the original deal with Waitrose.” She declined to discuss the total amount Allbritton invested, if he had a current role in the company, or any other details.

A rep for Allbritton did not return calls for comment.

The Times also reported that Charles is losing some key staffers including Robert Higdon, executive director of his foundation in Washington. Higdon recently resigned after 14 years of bringing wealthy American donors to the prince’s charities.

A spokeswoman for the foundation said Higdon declined to comment but that the timing of his resignation was not linked to the Allbritton flap.

Read earlier: Joe and Barbie Allbritton make royal wedding guest list, 4/24/11