At tonight's BFI showing of Dr Who Let's Kill Hitler Steven Moffat while conducting a Q & A confirmed that there will be a new companion in series 7. The tweet from DWMteets ( the official twitter account of Doctor Who Magazine)
@DWMtweets - Doctor Who MagazineOh, and a new companion! Yes, confirmed by @steven_moffat tonight! ;)
More on this when there are more details but it looks like Matt Smith will be having a new traveling partner.