Actor and presenter Kelly Brook says she was forced to intervene after the new British prime minister Boris Johnson hurt himself at a dinner party during a game of thumb wars.

Speaking on Heart Radio in the UK, Brook said that some years ago she sat next to Johnson during a star-studded party, which was also attended by veteran singer Shirley Bassey.

The 39-year-old said later in the evening that Johnson (55) began to play fight with another guest after a round of the popular children's game got out of hand, the Press Association reports.

Kelly Brook

Johnson's then-wife called on Brook to break up the pair, who she said had been causing a "fracas".

Brook said that after discovering the Tory leader had dislocated his thumb, she comforted him and iced his finger with frozen peas.

"I've met Boris a few times. I was actually talking earlier about a dinner party that I was invited to," Brook said.

"I sat next to him, and Shirley Bassey was there, and he was asking Shirley to sing, and she told him off because Shirley sings when she wants to sing.

"That evening we were all having drinks, like a bit of a party, dancing, and he started play fighting with some of the other guests.

"And it all started getting a bit out of hand and his wife came over to me and said: 'Kelly, Kelly, they're getting very rough with each other.

"'They're hurting Boris. Can you go and do something?'

"So I was chosen to go and split up this little kind of fracas between Boris and one of these other guys at the party, and they had been playing thumb wars or something.

"I'm not joking, they were playing thumb wars. Our prime minister was playing thumb wars.

"And he lost so badly that he actually dislocated his thumb and he was very upset about it so I had to comfort him and get frozen peas from the freezer and ice his thumb. Yeah, true story."

When he was Lord Mayor of London, Brook and Johnson worked together to launch the 2010 Mayor of London's Sky Ride, a free mass-participation cycling event held in the city.