From BeatlesWiki
The Rolling Stones record their version of
I Wanna Be Your Man, written by John Lennon and Paul McCartney. Supposedly, either The Rolling Stones or their manager Andrew Loog Oldham (accounts vary) ran into
John Lennon and
Paul McCartney on the street after they came back from an awards luncheon. The Rolling Stones asked for a single from them, so they went back into rehearsal to finish writing the song, writing in the corner of the room while The Rolling Stones watched.
John Lennon lated commented, "That shows how much importance we put on it. We weren't going to give them anything great, right?"
Source
- Paul McCartney, Many Years From Now, p. 154, quoting an interview in Hit Parader.