VIDEO : How Would You Act If You Joined Paul McCartney Onstage? Probably Just Like Dave Grohl

Foo Fighters frontman Dave Grohl has had plenty of opportunities to perform with Paul McCartney. But that didn't stop him from acting like a teenager as he joined Sir Paul's band for a raucous version of "I Saw Her Standing There" Saturday night at the O2 Arena in London.
The gig was McCartney's first show of a two-month summer tour that will see him performing in his hometown of Liverpool, England, as well as Amsterdam, Paris, Philadelphia, and Chicago.
Also at the O2 show, McCartney dusted off an odd number from his McCartney II disc, "Temporary Secretary."??