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

Watch: Taylor Swift and Fifth Harmony perform 'Worth It' together live.

Fifth Harmony became Sixth Harmony last night on the 1989 World Tour, as they joined Taylor Swift on-stage to perform 'Worth It' together live.

GIRL POWER!!!!!!

Watch fan-filmed footage of the performance below...