Pet said:

I was having a look at Goldfrapp tweets and sometimes Alison will say that she is at the, NT. Could someone please tell me what that is?? Many thanks! xx

The NT is the National Theatre.  See here:

http://en.wikipedia.org/wiki/Royal_National_Theatre

Until I looked at Wiki, I had no idea that it was the Royal National Theatre -- I'm pretty sure that it used to be just the National Theatre.  Most people familiar with the place, I think, would call it the NT.