Imagine strolling down New York Times Square, side by side bae and your favourite song suddenly starts playing with a flash mob dancing along to it.

This was the surprise that awaited Derin as she and her fiancé exited a H&M store in the Times Square area, New York.

In the video, a flash mob dances along to Wizkid's "On Top Your Matter", to the excitement of Derin who whips out her phone and records, completely oblivious to the fact that the entire show is about her.

After the dance, the flash mob make their way  towards the couple and leads Derin to the centre of the circle, it is at this point she realises what's going on.

See her priceless reaction when her fiancé gets on one knee to propose.