coup de main - noun
\ˌkü-də-ˈmaⁿ
Definition of coup de main : an attack that achieves complete surprise.

Florence Welch & The Rolling Stones performing 'Gimme Shelter' together live.

This is a bit old - not sure how I missed it! - but Florence Welch joined The Rolling Stones on-stage at their London show last year to perform 'Gimme Shelter' together.

Watch the performance below...