ROCK HILL, South Carolina — Joe Biden forgot the prime minister of the United Kingdom's name after touting his foreign policy knowledge.

“I don’t know the new prime minister of England. He looks like Donald Trump, I know that," the former vice president said at a town hall hosted by Clinton College. Biden made the comment while answering a question about his foreign policy platform. Biden claimed he was the only Democratic president candidate with relationships with foreign leaders.

Boris Johnson became prime minister on July 24, having previously been foreign secretary, and mayor of London for seven years, among other roles.

It's hardly the first time Biden, former chair of the Senate Foreign Relations Committee, has confused the names of foreign leaders, particularly in Great Britain. At a May 4 fundraiser, Biden, 76, flubbed the name of then-British Prime Minister Theresa May, calling her by former Prime Minister Margaret Thatcher's name.

Biden's verbal mistakes have concerned domestic issues, as well. Addressing the Iowa Asian and Latino Coalition in mid-August, Biden said, "Poor kids are just as bright and just as talented as white kids —," correcting himself, "— wealthy kids, black kids, Asian kids.”

[ Also read: 'He keeps saying stupid stuff': Iowa Democrats concerned about Biden's gaffes]