Paul McCartney has revealed that he sat in on rehearsals for Jack White when the White Stripes singer was nervous about performing for Barack Obama and family earlier this year (June 2).

The ex-Beatle was at the White House collecting the US Library of Congress’s Gershwin Prize for Popular song when he came across a shaken Jack White rehearsing ahead of his performance of ‘Mother Nature’s Son’ for the US presidential family.

Macca, 68, said: “There was a rehearsal first of all in the afternoon, and I came in and Jack’s standing there, and I could see he was nervous, so I thought it would be good for them to have a rehearsal with me sat there.”

He added, "Get over the nerves, because it's going to be worse - he's going to be sitting there and Michele and the kids and then all the crowd. But I thought Jack's performance was great, very sensitive."

Watch Paul performing and accepting his Gershwin Prize from Barack Obama below: