Sir Paul McCartney surprised his son James by joining him on stage last night (27.03.13).

James was playing a small show at London's Ambassadors Theatre as a warm up to his forthcoming US tour, and had recruited The Rolling Stones guitarist Ronnie Wood to join him on guitar for a track. However, he was shocked when his father also jumped behind the piano with them both for the song 'New York Times'.

Ronnie's wife, Sally, later tweeted: ''So lovely to have @JamesMcCartney_ @PaulMcCartney & @RonaldDavidWood up on the stage playing together ~ #beautiful (sic)''

After performing, Paul rejoined his wife, Nancy, and two of his daughters, Stella and Mary, in the audience to watch the rest of the show.

James, 35, is preparing his first ever full-length album, called 'Me'.

Speaking about the record he said: ''For my first album I wanted to make a record that
would be intimate, deeply personal, and honest.

''An album
 that would say, 'This is who I am... both musically and personally. This is
 me.' ''

Paul did drop by the studio to help James record, with them tweeting a picture together behind the mixing desk earlier this year. The father and son are no strangers to working together, as James has previously contributed to his dad's albums including 1997's 'Flaming Pie' and 2001's 'Driving Rain'.

James is embarking on a 47-date US tour which will start on April 6 in Portland, Oregon.