British Prime Minister David Cameron is reported to have attended a New Year's party thrown by Blur bassist Alex James at his country house where he sipped wine and engaged in a spot of "dad dancing".

The Sun newspaper reports that Cameron and his wife, Samantha, were invited to the bash and claims that fellow guests said that James tried to persuade Cameron to sing karaoke. 

"David and Samantha looked to be having a fun time," said a source. "Although his security was with him to make sure none of the 200 guests got any pictures, it was definitely an off-duty night for the PM.

"He seemed to be sipping on red wine throughout the night, although [he] wasn't drunk - which makes his dad dancing even less excusable." 

The source added: "Alex kept trying to get him to sing karaoke and looked like he was almost persuaded. But that was probably the point he realised it was time to go home. Samantha was a great laugh and dancing around. It looked like she was playing a leg as a guitar as one point."

James was previously spotted with Cameron and Top Gear presenter Jeremy Clarkson at his cheese festival in 2011.

James said at the time, "Politics is not my thing, but I was absolutely delighted when the Camerons came. It was a great party and the PM had a great time."