Talking at last nights Bafta Television awards Steven Moffat confirmed that Series 8 is currently being written, he has said:
"... series eight is absolutely, definitely
confirmed. It is real and it's happening - it's [taking up] most of my time at
the moment."
Jenna-Louise Coleman has confirmed that she will be taking part in series 8, Matt Smith's involvement is unknown at present. The 2013 Christmas special should start filming in August / September