Former Beatle pays tribute to victims at a show in Delaware
The former Beatle is currently in the middle of a European tour
The former Beatle was allegedly first introduced to cannabis by Bob Dylan in 1964
The former Beatle played a show at the Liverpool Echo Arena on Thursday (May 28)
The former Beatle was asked to play Ross Geller's British father-in-law
The former Beatle played the 'McCartney II' track at the O2 Arena on Saturday (May 23)
McCartney also played 'Temporary Secretary' from 'McCartney II' live for the first time
Pair have worked together on a number of recent tracks
Singer has enlisted Gaga for soundtrack to animated film 'High in the Clouds'
The pair recently collaborated on tracks 'All Day', 'Only One' and 'FourFiveSeconds'