Sir Paul McCartney serenaded one lucky child with his harmonica on his road trip with girlfriend Nancy Shevell.

McCartney treated the boy to a song after his parents informed the star that he was named after the Beatles hit 'Hey Jude'.

Don Dunavin, wife Lori and their child Jude, bumped into McCartney, who is currently driving along Route 66 with Shevell, in Amarillo, Texas.

"I took two steps forward and shook his hand. He went to Jude, grabbed his hand and started talking to him. After we told him his name, he said, 'I got something for him',” Mr Dunavin said.

He added that McCartney only stopped briefly when he asked his wife to take a pictures before playing on.

His wife told the Mirror: "Now it doesn't matter if Jude gets teased. The man himself played the harmonica for him."

McCartney is understood to be spending the whole of August driving across the famous route in America.

(by Jason Gregory)