iOS / Swift2.1: get NSDate from timestamp for Message class?

I am trying to get the Date for the Message object using the timeStamp property:
I have tried converting the timeStamps im getting using the following, but it gives strange dates:
For example timestamp from a message I just sent: 1457108359677 gives date: 05/12/48143 03:07 (DD/MM/yyyy HH:MM)
That does not seem right?
The code i am using is the following:

Hi Bilal,

Perhaps this will be helpful: